A comparative review of self-rotating and stationary twisted tape inserts in heat exchanger

Renewable and Sustainable Energy Reviews 53 (2016) 433–449

Contents lists available at ScienceDirect

Renewable and Sustainable Energy Reviews journal homepage: www.elsevier.com/locate/rser

A comparative review of self-rotating and stationary twisted tape inserts in heat exchanger Cancan Zhang a, Dingbiao Wang a,n, Kun Ren b, Yong Han a, Youjian Zhu a, Xu Peng a, Jing Deng a, Xiying Zhang a a b

School of Chemical and Energy Engineering, Zheng Zhou University, Zheng Zhou 450001, China North China University of Water Resources and Electric Power, Zheng Zhou 450001, China

art ic l e i nf o

a b s t r a c t

Article history: Received 10 April 2015 Received in revised form 15 May 2015 Accepted 21 August 2015

Heat transfer enhancement techniques are popularly used in various engineering applications such as heat exchanger, air conditioning, chemical reactors and refrigeration systems. Twisted tape is one of the most important passive techniques, which has been proved to disturb the flow fluid in tube and then strengthen the heat transfer efficiency. This paper conducted comprehensive and comparative review on experimental and numerical works taken by researchers on self-rotating and stationary twisted tapes. It is found that the heat transfer enhancement and the function of online anti-scaling and descaling in tube can be obtained with the self-rotating twisted tapes. Meanwhile, the tube with self-rotating twisted tapes gives the lower pressure drop. Both heat transfer coefficient and friction factor increase with the decreasing of twisted ratio. The twisted tapes combined with different modified techniques are the new development directions of heat transfer enhancement. The appropriate twisted tape modification is necessary for heat transfer enhancement with pressure loss penalty at a reasonable level. & 2015 Elsevier Ltd. All rights reserved.

Keywords: Heat transfer Friction factor Twisted tape Self-rotating Stationary

Contents 1. 2. 3. 4. 5.

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Main categories of twisted tapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The main mechanism of heat transfer enhancement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Performance evaluation parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Development of self-rotating twisted tapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1. Impact of self-rotating twisted tapes on the enhancement efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2. Impact of self-rotating twisted tapes on the anti-fouling and descaling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. Development of stationary twisted tapes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1. Impact of typical twisted tapes on the enhancement efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2. Impact of varying length, alternate-axes twisted tapes on the enhancement efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3. Impact of multiple twisted tapes on the enhancement efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4. Impact of twisted tapes with fins, winglet on the enhancement efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5. Impact of twisted tapes with slots, holes, cuts on the enhancement efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.6. Impact of helical and screw twisted tapes on the enhancement efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.7. Impact of center-cleared twisted tapes on the enhancement efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.8. Impact of tapes with other kinds of modifications on the enhancement efficiency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

n

Corresponding author. E-mail addresses: [email protected] (C. Zhang), [email protected] (D. Wang), [email protected] (K. Ren), [email protected] (Y. Han), [email protected] (Y. Zhu), [email protected] (X. Peng), [email protected] (J. Deng), [email protected] (X. Zhang). http://dx.doi.org/10.1016/j.rser.2015.08.048 1364-0321/& 2015 Elsevier Ltd. All rights reserved.

434 434 435 436 437 437 438 439 439 442 443 443 443 444 444 445 446 447 447 447

434

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

Nomenclature a* B C de ds D DP DR DS DV DW e f h H L LA LC n N Nu ΔP PR Re

clearance ratio of the twisted tape, dimensionless thickness of twisted tape, m distance between inner wall of the tube and twisted tape insert, m characteristic length, m diameter of semicircle groove, m the inner diameter of the tube, m diameter of perforated, m diameter ratio, dimensionless serration depth, m depth of V cut, m depth of wing cut, m the rib height, m friction factor, dimensionless the convective heat transfer coefficient, W m
2 K
1 the half-length of twisted pitch, m length of the tube, m alternate length, m pitch length of circular-ring tabulators, m rotate speed, m s
1 the number of regular spaced twisted tape, dimensionless Nusselt number, dimensionless pressure drop, Pa pitch ratio of dimple Reynolds number, dimensionless

1. Introduction The consumption of oil, gas and coal in the final energy causes the global warming and pollutant emission. More efficient engines with less waste heat are being developed. As a general device, the heat exchanger plays an important role in the recovery process, air conditioning, refrigeration systems, and thermal power plants [1–5], etc. The performance of the heat exchanger influences system efficiency as well as its cost. Therefore it is important to enhance the heat transfer performance to achieve sustainable energy development. In general, heat transfer augmentation methods can be classified into three broad categories: active, passive and compound methods [6]. The active method involves some external power input for the enhancement of heat transfer. On the contrary, the passive method can enhance the heat transfer by using modified surfaces or geometries such as rough surfaces, extended surfaces, tube inserts, etc. As the name implies, the compound method combines the passive method with the active method. To achieve an optimal heat transfer rate at an economic pumping power, the passive method is popularly used. As one of the passive method techniques, tube inserts technology has been widely used in the heat exchanger such as twisted tape, helical spring [7], ribs [8], conical nozzle, and conical ring [9–11], etc. The tube inserts can be divided into two broad categories: stationary and self-rotating. The stationary inserts have the relatively fixed position in plain tube. The self-rotating inserts are defined as such inserts which can automatically rotate while the fluid flows through the tube. The self-rotating inserts can strengthen the heat transfer efficiency and achieve the on-line anti-scaling and descaling effect.

RB RC RP RS SP SS T WP WS WV

winglet blockage ratio, dimensionless pitch ratio of converging section and diverging section, dimensionless perforation pitch ratio, dimensionless free space ratio, dimensionless spaced-pitch length of perforated, m the distance between two semicircle groove, m temperature, K width of peripheral cut, m serration width, m width of V cut, m

Greek symbols β λ δ μ ρ η

angle of attack, degree thermal conductivity, W m
1 K
1 twisted tape pitch ratio, dimensionless dynamic viscosity, kg m
1 s
1 density, kg m3 thermal performance factor, dimensionless

Subscripts w T 0

tube wall tube inserted with twisted tape plain tube

As one of the major tube inserts, twisted tape can improve heat transfer rate, which has been widely studied by many scholars and popularly used for heat exchangers. Although literatures [12,13] comprehensively review the thermal performance twisted tape in heat exchangers, the thermal and anti-fouling performance of selfrotating twisted tape will be focused in the present paper. The findings provide useful references for future development of twisted tape. The present review is organized as follows: main categories of twisted tape, the main heat transfer enhancing mechanism and performance evaluation parameters are introduced in Sections 2–4, respectively. Sections 5 and 6 present the developments of self-rotating and stationary twisted tapes, respectively. The discussion and conclusion are drawn according to the previous reviews and analysis in Sections 7 and 8, respectively.

2. Main categories of twisted tapes Large numbers of experimental and numerical work have been carried out by researchers and engineers to study the thermohydraulic performance of various twisted tapes from the 1960s onwards. Twisted tape can be manufactured in a variety of forms by suitable techniques using the aluminum, copper, steel or polymer plastic. It can be applied in various areas in certain conditions. Firstly, it is indispensable to define some important parameters used in this report to facilitate understanding and discussing the characteristics of twisted tape. Fig. 1 shows the sketch map of typical twisted tape. The basic parameter for twisted tape is twist ratio. The twist ratio is defined as follows:

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

Y = H /D

(1)

H is the half length of twist pitch, which is defined as the distance between two points that are on the same plane, measured parallel to the axis of a twisted tape. B is the thickness of twisted tape and D is the inside diameter of the tube. The configuration sketches of self-rotating twisted tapes are shown in Table 1. The commonly used stationary twisted tape can be classified into typical twisted tape, multiple twisted tapes, varying length, alternate-axes and pitches twisted tape, twisted tape with slots, holes, cuts, twisted tape with rod and varying spacer, twisted tape with attached fins and tapes with different surface modifications, which are shown in Table 2.

3. The main mechanism of heat transfer enhancement Twisted tapes have been generally applied as heat transfer enhancing devices in heat exchanger. In this part the main and effective mechanisms of heat transfer enhancement are analyzed for better understanding of twisted tape property. The velocity vector contour of a plain tube and a tube inserted with twisted tape are shown in Figs. 2 and 3, respectively. The fluid in tube with twisted tape in Fig. 3 presents the helical flow, the

435

cutting speed and the radial velocity of flow near the wall have been improved compared to the plain tube. The centrifugal force induced by tangential velocity accelerates the mixing between the mainstream zone and the near wall zone [18]. The main mechanisms of heat transfer enhancement due to twisted tape include: 1. The reduction of a hydraulic diameter of heat transfer tube causes an increase of flow velocity and curvature, which in turn can increase the shear stress near the wall and drives secondary motion. 2. The velocity increase near the tube wall due to the blockage of the twisted tape which reduces thickness of the boundary layer. 3. The velocity increase due to the helical flow following the twisted tape. 4. The induced swirling flow makes a better fluid mixing between the core and the near-wall flow regions. This swirling flow can be seen in Fig. 4. For single-phase fluid flow without phase change, heat transfer resistance mainly exists in the boundary layer. To enhance the heat transfer coefficient, the researchers should focus on reducing the thickness of boundary layer to get greater convective heat transfer. As one of the most favorable passive techniques, twisted tape insert is a kind of vortex generator which can break the boundary layer and reduce the thickness of the laminar bottom layer. It has been proposed that such tapes induce turbulence and superimposed vortex motion causing a thinner boundary layer. Consequently, this results in higher heat transfer coefficient.

Fig. 1. Structure sketch map of twisted tape.

Table 1 Configuration sketches of the self-rotating twisted tapes. Configuration

Illustration

Name

Reference

1 – Tube bearing, 2 – spindle, 3 – tube, 4 – twisted tape

Typical twisted tape

[14–21]

1 – Tube bearing, 2 – spindle, 3 – tube, 4 – twisted tape with oblique teeth

Oblique teeth twisted tape

[22]

1 – Tube bearing, 2 – straight strip with elliptical teeth and broken Straight strip with elliptical edge, 3 – spiral line, 4 – elliptical teeth, 5 – straight strip teeth and broken edge

[23]

–

Miniature hydraulic turbine

[24–28]

–

Triangular groove twisted tape

[29,30]

–

Semicircle groove twisted tape

[31]

–

Regularly spaced twisted tape

[32]

–

Helically twisted tape

[33]

436

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

Table 2 Configuration sketches of the stationary twisted tapes. Configuration

Name

Reference Configuration

Name

Reference

Typical twisted tape

[34–42]

Twisted-tape with V-winglets

[43]

Perforated twisted tape

[44,45]

Left–right twisted tape

[46]

Notched twisted tape

[47]

Right and left helical screw-tape

[48]

Jagged twisted tape

[47]

Helically twisted tape

[49]

Twisted tape consisting wire nails

[50]

Perforated helical twisted-tape

[51]

Center-cleared twisted tape

[52–56]

Twisted tape with geometrical progression ratio

[57]

V-cut twisted tape

[58]

Double twisted tape

[59–63]

Twisted-tape with alternate axes

[64,65]

Triple twisted tape

[66]

Serrated twisted tape

[67]

Ribbed spiky twist tape

[68,69]

Twisted tape consisting of centre wings and alternate-axes

[70]

Twisted tape with circular-rings

[71]

Peripherally-cut twisted tape with an alternate axis

[72]

Staggered twisted tape with central holes

[73]

Square-cut twisted tape

[74–76]

Elliptic-cut twisted tape

[77]

Helical screw tape

[78–80]

Regularly-spaced twisted tape

[81]

4. Performance evaluation parameters In order to evaluate the different kind of twisted tapes, the uniform performance parameters have been proposed. There exist some non-dimensional parameters for defining the properties of twisted tape: Reynolds number (Re), Nusselt number (Nu), friction factor (f), and thermal performance factor (η). The Reynolds number (Re) is determined by:

Re = deuρ /μ

(2)

The Nusselt number (Nu) can be calculated according to the correlation:

Nu = hde /λ

(3)

Where h is the convective heat transfer coefficient and λ is the thermal conductivity. The friction factor (f) in term of pressure drop across the tube can be calculated as:

f=

2ΔPde ρu2L

(4)

Where ΔP is the pressure drop in the whole tube, de is the tube side hydraulic diameter, and u is the mean fluid velocity of the whole tube. The thermal performance factor (η) based on the tradeoff between increased heat transfer and friction factor is the most widely used criteria, and it is the comparison of heat transfer coefficients between the tube fitted with twisted tape and plain tube under the constant pumping power condition, which is defined as:

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

437

5. Development of self-rotating twisted tapes 5.1. Impact of self-rotating twisted tapes on the enhancement efficiency

Fig. 2. The velocity vector contour of plain tube.

Fig. 3. The velocity vector contour of tube inserted with twisted tape.

Fig. 4. The flow characteristic with twisted tape [59].

η=

NuT /Nu0 (fT /f0 )1/3

(5)

Where NuT is the Nusselt number of the tube with twisted tape, Nu0 is the Nusselt number of the plain tube; fT is the friction factor of the tube with twisted tape, and f0 is the friction factor of the plain tube. The Reynolds number, Nusselt number, friction factor and thermal performance factor are all dimensionless numbers. So they can be employed to estimate the performance of different configurations of twisted tapes.

Large numbers of experimental work and theoretical researches have been carried out to study the performance of various self-rotating twisted tapes. The configuration sketches of the selfrotating twisted tapes are shown in Table 1. The twisted tape which is fixed with the rotating device on both ends of heat exchange tube can rotate around the center by itself while the fluid in tube flows. The comparative performance of various self-rotating twisted tapes has been summarized in Table 3. The correlations of selfrotating twisted tapes are shown in Table 4. All the performances of tube with a self-rotating twisted tape are compared with that of a plain tube without twisted tape. A conclusion can be drawn that both the heat transfer rate and the pressure drop increase with the tube fitted with self-rotating twisted tape. Researchers, like Lin et al. [14] theoretically and experimentally analyzed the rotating speed of self-rotating twisted tape. It is found that the axial speed of the flow and the pitch of the twisted tape have the significant influence on the rotating speed of the self-rotating twisted tape. Li [15] experimentally studied the working characteristics of self-rotating twisted tape. The increase of the total heat transfer coefficient is between 12% and 62%. Zhang et al. [16,17] proposed the heat transfer enhancement mechanisms of heat exchanger tubes with self-rotating twisted tape inserts. The results indicate that for the heat transfer enhancement, the increase in the velocity near the tube wall and the reduction effect of the equivalent diameter are the main factors when yZ10, the helical flow effect is the main element when yo10, the secondary recirculation becomes the main factor when yr1. In order to visually describe the pressure drop characteristics difference between the self-rotating twisted tape and stationary twisted tape, Feng et al. [19] experimentally and numerically studied pressure drop characteristics of 3 types of self-rotating twisted tape. The results show that the pressure drop of the tube fitted with self-rotating twisted tape and stationary twisted tape is about 2.02 and 2.73 times compared to smooth tube, respectively. The fluid flow axial velocity, the width and the pitch of the twisted tape are the main influencing factors of the pressure drop of the twisted tape. Lin [21] found that the polypropylene twisted tapes have better comprehensive performance than the aluminum twisted tapes. Yu et al. [22] made a further experiment to investigate the self-rotating oblique teeth twisted tape with water as working fluid. The results show that the oblique teeth twisted tape could automatically rotate and enhance heat transfer with low flow velocity of 0.5 m/s. This is because of the additional rotating moment formed by the oblique teeth on the twisted tape. Due to the difficulty of manufacturing twisted tape with teeth, straight strip-insert with elliptical teeth and broken edge on both sides was put forward by Peng et al. [23]. The experiment results indicated that it could work reliably at the flow speed of 0.5 m/s in tube and increase the heat transfer coefficient in tubes by 171%. Furthermore, Lin [24] devised the miniature hydraulic turbine and experimentally examined the performance of flow resistance and heat transfer in tube with miniature hydraulic turbine. According to the moment of momentum theorem, Lin et al. [25] studied the rotational performance of hydraulic turbines with different size by experiments. The axial velocity of the flow and the thread pitch of the vane are the main factors in influencing the rotational speed of the hydraulic turbine which obtained from the results. Lin et al. [26,27] experimentally and theoretically investigated the heat transfer enhancement of the hydraulic turbine. The results indicate that the use of miniature hydraulic turbine leads to maximum heat

20.07–265.74% 14.49–33.04% Re¼ 5000–55,000

0.01–0.68 times 0.01–0.28 times Re¼ 1730–44,500

Re¼ 10,000–100,000 Water

3.25 kPa/m while the flow velocity in tube is 0.625 m/s 0.13–0.16 times 1.71 times compared with smooth twisted tape 0.28–0.56 times u¼ 0.3–1.1 m/s

1.02 times 75.48–101.57%

Water Helical twisted tape Ou [33]

Water Triangular groove twisted tape

Oblique teeth twisted tape Yu et al. [22]

Zhan [30]

Typical twisted tape Lin [15]

Peng et al. [23] Straight strip with elliptical teeth and broken edge Lin et al. [27] Miniature hydraulic turbine

Name Author

Water

Water

The minimum speed of tube fluid flow is generally in 0.7 m/s The minimum speed of tube fluid flow is generally in 0.5 m/s The minimum speed of tube fluid flow is generally in 0.5 m/s The rotating speed was 850 r/min when the flow velocity in tube was 1 m/s The minimum speed of tube fluid flow is generally in 0.33–0.46 m/s The minimum speed of tube fluid flow is generally in 0.3 m/s

Water

0.5–0.7 times 12–62%

Working fluid Condition Characteristics of rotating

Re¼ 3000–65,000, Y ¼ 3–7 Re¼ 11,000–30,000

Flow resistance increment Heat transfer enhancement

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

Table 3 The comparative performance of self-rotating twisted tapes.

438

enhancement efficiency up to 1.62 times and the flow resistance up to 1.16 times. Follow-up research was carried out by Zhan [30] regarding the influences of the triangular groove twisted tape insertion with a twist ratio of 5.0 and 7.0. The results reveal that the rotational capability and pressure drop of triangular groove twisted tape are greatly improved because of the boundary layer disturbed by the triangular groove. Sun [31] experimentally studied the thermal and friction performance of semicircle groove twisted tape. It is found that the larger the semicircle diameter, the greater the Nusselt number. The regularly spaced twisted tape has experimentally studied by Liu [32]. The results present that the regularly spaced twisted tape perform lower heat transfer and friction factor values than the full-length twisted tape. The larger the twisted ratio is, the feebler the influences of distance to heat transfer and flow resistance characteristics. Ou [33] carried out a study to research the heat transfer and pressure drop in a tube fitted with helical twisted tape. With the increasing of W/D, both the Nusselt number and the friction decrease. In particular, the friction and Nusselt number increases with the increase of twist rate Y, which is different from the smooth twisted tape. 5.2. Impact of self-rotating twisted tapes on the anti-fouling and descaling Fouling is formed on the tube wall in the heat exchanger, which can lead to decline of production capacity, material loss, increase the energy consumption. The experimental results show that the main mechanism scaling in heat exchanger is crystallization scaling combined with particulate scaling. The crystallized salt builds up in heat transfer tube so quickly that its thickness can increase to several mm within one hour. In order to solve this problem, kinds of self-rotating twisted tapes have been put forward by many researchers. The anti-fouling and descaling mechanism of self-rotating twisted tape is mainly disturbing the boundary layer. The self-rotating twisted tape can rotate and generate torsional vibration wave under a certain flow velocity in tube. The edges of twisted tape strike and extrude the fouling by the radial vibration. The rotating twisted tape generates the circumferential shear stress and scrapes the inner fouling in tube. So it can automatically clean the existing fouling, prevent fouling from ever forming and have anti-fouling function in the clean heat transfer surface. The heat transfer coefficient and crystallization of salt layer thickness of the heat exchange tubes with or without the rotation of spiral were measured and compared by Li et al. [83]. The results show that the thickness of the crystal salt drops from 5.4 mm to 2 mm in a longterm continuous production, the rotation of the spiral will not damage and wear the tube wall. The contrast experimental researches on the adhesive velocity of fouling, the dynamic thermal resistance of fouling, the abrasion velocity of the tube wall for the heat exchangers between smooth tubes and tubes with the self-cleaning plastic twisted tape were carried out by Zhang et al. [84]. The results indicate that the average adhesive velocity of fouling for the tubes inserted with twisted tape is only 54% that of the smooth tubes, the average dynamic thermal resistance of fouling is 30% smaller than that of the smooth tube. Twisted strip with oblique teeth, which could be used to automatically remove fouling and enhance heat transfer with flow velocity of 0.5 m/s, was proposed by Yu et al. [85]. The total moment of force is increased by 75–101% compared with the smooth twisted strip. Yu et al. [86] found that the dissymmetrical oblique teeth distributed evenly on both surfaces of strip. The overall operation moment is increased by 277% and the heat transfer coefficient is increased by 22.8–30.7% over the smooth twisted strip.

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

439

Table 4 The correlations of self-rotating twisted tapes. Authors

Working fluid

Condition

Configuration

Correlations

Li [15]

Water

Re¼ 10,000–80,000

Y ¼3–7 W¼ 11–14 Pr¼ 3.6–5.35

Nu = 0.054W 0.1256Re0.8078Pr1/3(μ/μw )0.14 f = 1.49W 0.1046H −0.1559Re−0.3037 n = 30u/H − 91.8W −0.3811H 0.1790

Lin [21]

Water

Re¼ 5000–65,000

Y ¼4–7 W¼ 10–14

Nu = 0.1095W 0.3016Y −0.1412Re0.7821Pr1/3(μ/μw )0.14 f = 0.5721W 0.1963Y −0.1808Re−0.2296 n = 30u/Y − 0.01174/(W 2.2041Y 0.1203)

Zhai [28]

Water

Re¼ 10,000–70,000

Pr¼ 3.6–5.5

Nu = 0.0627Re0.7331Pr1/3(μ/μw )0.14

Zhan [29]

Water

Re¼ 6000–55,000

Y ¼5–7 W¼ 20–22 D¼ 37

Nu = 0.24114(W /D)−0.08424 Y −0.4014Re0.62691Pr1/3(μ/μw )0.14 f = 3.1369(W /D)−1.31801Y −0.03537Re−0.52139 n = 298.27(W /D)−9.6377Y −3.4898u4.1585

Sun [31]

Liu [32]

Ou [33]

Yin et al. [82]

Water

Water

Water

Water

Re¼ 5000–50,000

Re¼ 8000–65,000

Re¼ 5000–55,000

Re¼ 8000–60,000

Y ¼4–7 W¼ 10–14

Nu = 0.0587(W /D)0.052(ds /W )0.208(S /H )−0.106Y −0.396Re0.544Pr1/3(μ/μw )0.14

Y ¼4–6 N¼ 3–9 SS ¼ 0.4–1.0 W¼ 17–23 D¼ 37 Pr¼ 3.2–5.5

Nu = 0.59N 0.008Y −0.0474(1 + SS )0.0619(W /D)0.1282Re0.5182Pr0.4

Y ¼2–4 W¼ 6–8 D¼ 37 δ ¼ 1.5–2.5

Nu = 1.6505(W /D)0.6642Y 0.1833Re0.5008δ −0.1749Pr1/3(μ/μw )0.14

Y ¼5–7 W¼ 18–22 D¼ 37

6. Development of stationary twisted tapes A variety of stationary twisted tape inserts are commonly investigated and applied in the heat exchangers to enhance the heat transfer efficiency. The sketch map of twisted tape device is shown in Table 1. The correlations of stationary twisted tapes are summarized in Table 5. Compared to the self-rotating twisted tapes, the stationary twisted tapes cannot rotate automatically and have higher pressure drop. Typical twisted tapes have been studied by a large number of researchers. These tapes have length equal to that of exchanger tube. 6.1. Impact of typical twisted tapes on the enhancement efficiency In order to achieve the abilities of twisted tape in nanofluid, Azmi et al. [34] experimentally investigated the convective heat transfer coefficient and friction factor of TiO2/water nanofluid flow in a tube with twisted tape inserts. In the tested range, the heat transfer coefficient increases with decrease in twist ratio for water and nanofluid using the twisted tapes. Kanizawa et al. [35]

f = 1.15(W /D)0.44 (ds /W )0.05(S /H )−0.045Y −0.1Re−0.32

f = N 0.1156Y −0.1675(1 + SS )0.4075(W /D)0.1673Re−0.3354

f = 14.0795(W /D)0.4096Y 0.4690δ −1.6845Re−0.3521 n = 19.53(W /D)−1.3722Y 0.6137δ 0.4631u − 122.97

Nu = 0.11717(W /D)0.4115Y −0.0363Re0.6832Pr1/3(μ/μw )0.14 f = 0.15346(W /D)0.11283Y −0.10154Re−0.18156

evaluated the heat transfer enhancement and pressure drop for R134a two-phase flow in tubes with twisted tape inserts. Experiment results are obtained that the use of reduced twist ratio value provides greater overall heat transfer performance and the heat transfer coefficient increments up to 45%. The pressure drop penalty sharply decreases with the increase of vapor quality. Meanwhile, Mogaji et al. [36] experimentally researched the heat transfer coefficient and pressure drop during two-phase flow of R134a in a horizontal tube fitted twisted tape inserts. The results are observed that the heat transfer coefficient enhancements and pressure drop penalties are respectively up to 36% and 133% compared with the plain tubes. The effects of twist ratios and clearance ratios were experimentally investigated by Basa and Ozceyhan [37]. The results indicate that the Nusselt number increases with the decrease of clearance ratio and twist ratio also increase with Reynolds number. Mokkapati and Lin [39] numerically investigated gas to liquid heat transfer performance of concentric tube heat exchanger with twisted tape inserted corrugated tube. The results reveal that the transfer enhancement rate in annularly corrugated tube heat

440

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

Table 5 The correlations of stationary twisted tapes. Authors

Working fluid

Condition

Configuration

Correlations

Bas and Ozceyhan [37]

Air

Re¼5132–24,989

Y ¼2–4 C/W¼0.0178–0.0357

Nu = 0.406903Re0.586556Pr 0.38Y −0.443989(C /W )−0.055072 f = 6.544291Re−0.452085Y −0.730772(C /W )−0.1579 η = 11.7Re−0.19(H /W )−0.2Pr 0.4

Promvonge et al. [43]

Air

Re¼4000–30,000

Y ¼4, 5 RB ¼ 0.1–0.2

Combined twisted tape and V-winglet on two walls (2 W):

Nu = 0.2691Re0.6976Pr 0.4Y −0.2310RB0.1861 f = 16.3586Re−0.2860Y −0.4263RB0.6710 Combined twisted tape and V-winglet on four walls (4 W):

Nu = 0.3084Re0.6976Pr 0.4Y −0.2101RB0.1920 f = 26.1677Re−0.2860Y −0.3661RB0.8168

Thianpong et al. [45]

Nanan et al. [49]

Water

Air

Re¼5300–16,700

Re¼600–2000

H/W¼3–5 DP/W¼0.11–0.17 SP/W ¼0.4–0.8

δ¼ 1–2

Nu = 0.09Re0.768Pr 0.4(H /W )−0.325(SP /W )−0.133(DP /W )0.114 f = 9.03Re−0.272(H /W )−0.631(SP /W )−0.204 (DP /W )0.428 η = 1.764Re−0.059(H /W )−0.114 (SP /W )−0.065(DP /W )0.028

The empirical correlations developed for C-HTT:

Nu = 0.068Re0.792Pr 0.4δ −0.199 f = 19.6Re−0.301δ −1.498 η = 3.72Re−0.149δ 0.299 The empirical correlations developed for Co-HTT:

Nu = 0.047Re0.793Pr 0.4δ −0.179 f = 6.24Re−0.298δ −1.447 η = 3.806Re−0.147δ 0.303

Murugesan et al. [50]

Water

Re¼2000–12,000

Y ¼2.0–6.0

Nu = 0.063Re0.789Pr 0.33Y −0.257 f = 28.91Re−0.731Y −0.255 η = 1.919Re−0.032Y −0.165

Nanan et al. [51]

Murugesan et al. [58]

Air

Water

Re¼6000–20,000

Re¼2000–12,000

Y ¼3 PR ¼ 1.0–2.0 DP ¼ 0.2–0.6

Y ¼2.0–6.0

Nu = 0.035Re0.795Pr 0.4DP −0.068PR0.086 f = 1.915Re−0.299DP −0.068PR0.094 η = 1.058Re−0.145DP −0.045PR0.054

f= η=

Hong et al. [59]

Bhuiya et al. [62]

Water

Air

Re¼10,000–20,000

Re¼6950–50,050

H ¼ 11.25, 22.5 e¼0.5–1.1 α ¼60–180 Y ¼1.95–7.75

DV 1.148 W ]) (1 + [ V ])−0.751 W W D W 8.632Re−0.651Y −0.296(1 + [ V ])2.477(1 + [ V ])−1.914 W W D W 1.392Re−0.01Y −0.124(1 + [ V ])0.252(1 + [ V ])−0.058 W W

Nu = 0.0296Re0.853Pr 0.33Y −0.22(1 + [

Nu = 0.212Re0.766(e/D)0.267RC 0.0418(H /D)−0.216Y −0.256(α /360)−0.174 Pr 0.4 f = 95.167Re−0.26(e/D)0.812RC 0.0126(H /D)−0.313Y −1.279(α /360)−0.829

Nu = C1Re(0.0002Y

3− 0.0021Y2+ 0.0047Y + 0.5894)

Pr 0.33

(−0.00004Y 3+ 0.0015Y2− 0.0165Y − 0.4722)

f = C2Re

η = 41.176C1C2−0.6802Re(−0.0002272Y 3

3− 0.0031203Y2+ 0.015923Y − 0.13103)

2

C1 = − 0.0007Y + 0.0077Y − 0.0385Y + 0.477 C2 = − 0.0009Y 3 − 0.1015Y2 + 1.0842Y + 8.685

Eiamsa-ard et al. [64]

Water

Re¼5000–21,500

LA/H ¼ 0.5–2.0

Nu = 1.364Re0.472Pr 0.4(1 + LA/H )−0.437 f = 75.18Re−0.612(1 + LA/H )−0.623 η = 5.39Re−0.512(1 + LA/H )−0.224

Seemawute et al. [65]

Water

Re¼5000–20,000

Y ¼3.0 WP/W¼ 0.11–0.33

For the tube fitted with the peripherally-cut twisted tape with alternate axis

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

441

Table 5 (continued ) Authors

Working fluid

Condition

Configuration

Correlations

Nu = 0.422Re0.544Pr0.4(WP /W )−0.148 f = 59.08Re−0.651(WP /W )−0.18 η = 5.92Re−0.205(WP /W )−0.082 For the tube fitted witn the peripherally-cut twisted tape

Nu = 0.126Re0.658Pr 0.4(WP /W )−0.101 f = 18.82Re0.556(WP /W )−0.139 η = 3.37Re−0.14(WP /W )−0.028

Bhuiya et al. [66]

Air

Re¼ 7200–50,200

Y ¼ 1.92–6.79

Nu = C1Re(0.0002Y

3− 0.0013Y2+ 0.0094Y + 0.5746)

Pr 0.33

(0.00005Y 3+ 0.0017Y2− 0.0164Y − 0.5193)

f = C2Re

η = 41.176C1C2−0.6802Re(−0.000014Y 3

3− 0.000144Y 2+ 0.001755Y − 0.11379)

2

C1 = − 0.0017Y + 0.0179Y − 0.0962Y + 0.7734 C2 = − 0.0388Y 3 + 0.2484Y2 + 0.8462Y + 17.685

Eiamsa-ard et al. [67]

Eiamsa-ard et al. [70]

Air

Water

Re¼ 4000–20,000

Re¼ 5200–22,000

Y ¼4.0 WS/W ¼0.1–0.3 DS/W¼ 0.1–0.3

NuT /Nu0 = 3.877Re−0.103Pr 0.4(1 + (WS /W ))−0.13(1 + (DS /W ))0.67

Y ¼3.0 β ¼ 43–74°

Twisted tape with centre wings and alternate axes

fT /f0 = 3.63Re−0.057(1 + (WS /W ))−0.53(1 + (DS /W ))1.86

Nu = 0.385Re0.568Pr 0.4(1 + tan β )0.129 f = 20.445Re−0.504(1 + tan β )0.283 η = 6.772Re−0.194(1 + tan β )0.035 Twisted tape with centre wings Nu = 0.232Re0.595Pr 0.4(1 + tan β )0.202 f = 14.0395Re−0.505(1 + tan β )0.406 η = 4.629Re−0.194(1 + tan β )0.067

Eiamsa-ard et al. [71]

Air

Re¼ 6000–20,000

LC/D¼ 1.0–2.0 Y ¼3.0–5.0

For circular-ring alone:

Nu = 0.0895Re0.767Pr0.4(LC /D)−0.418 f = 0.994Re−0.093(LC /D)−0.418 η = 3.08Re−0.104(LC /D)−0.35 For compound device:

Nu = 0.326Re0.724Pr0.4(LC /D)−0.475Y −0.406 f = 13.99Re−0.202(LC /D)−0.92718Y −0.619 η = 4.63Re−0.111(LC /D)−0.166Y −0.199

Salam et al. [75]

Water

Re¼ 10,000–19,000

Y ¼5.25

Nu = 0.0002Re0.109Pr 0.3Y1.322 η = 1.2387Re0.339Pr −0.3Y −1.33

Murugesan et al. [76]

Water

Re¼ 2000–12,000

Y ¼ 2.0–6.0

Nu = 0.041Re0.826Pr 0.33Y −0.228 f = 6.936Re−0.579Y −0.259 η = 2.07Re−0.049Y −0.135

Patil et al. [80]

Ethylene glycol

Re¼ 10–1068

Y ¼1.44–4.66

⎛ μ ⎞0.14 Nu = 0.462Re0.792Pr 0.308Y −0.665⎜ ⎟ ⎝ μw ⎠ f = 78.44Re−0.932Y −0.789

Eiamsa-ard et al. [81]

Air

Re¼ 500–12,000

Y ¼6.0–8.0 RS ¼ 1.0,–3.0

Nu = 0.144Re0.697Pr 0.4Y −0.228(RS + 1)−0.179 f = 3.044Re−0.00Y −0.556(RS + 1)−0.34 η = 3.854Re−0.151Y −0.043(RS + 1)−0.065

Thianpong et al. [87]

Naphon [88]

Air

Water

Re¼ 12,000–44,000

Re¼ 7000–3,0000

Y ¼3–7 PR¼ 0.7–1.0

H/D ¼3.1–5.5

Nu = 0.014Re0.9(PR )−0.93Y −0.12Pr 0.3 f = 9.1Re−0.37(PR )−0.11Y −0.2

442

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

Table 5 (continued ) Authors

Working fluid

Condition

Configuration

Pr43

Correlations

Nu = 0.648Re0.36(1 + D /H )2.475Pr1/3 f = 3.517Re−0.414(1 + D/H )1.045

Zhang et al. [89]

Air

Re¼300–1800

Y ¼2.5 an ¼ 0.25–0.35

Triple twisted tapes

Nu = 2.0358Re0.238(a*)0.0492 f = 111.2919Re−0.7236(a*)0.6071 Quadruple twisted tapes

Nu = 1.5689Re0.2629(a*)0.0773 f = 181.521Re−0.732(a*)0.7234

Eiamsa-ard et al. [90]

Water

Re¼3000–27,000

DW/W ¼0.11–0.32 Y ¼3–5

For oblique delta-winglet twisted tape:

Nu = 0.18Re0.67Pr 0.4Y −0.423(1 + (DW /W ))0.982 f = 24.8Re−0.51Y −0.566(1 + (DW /W ))1.87 η = 2.04Re−0.042Pr 0.4Y −0.261(1 + (DW /W ))0.45 For straight delta-winglet twisted tape: Nu = 0.18Re0.675Pr 0.4Y −0.423(1 + (DW /W ))0.982 f = 21.7Re−0.45Y −0.564(1 + (DW /W ))1.41 η = 2.164Re−0.0435Pr 0.4Y −0.304(1 + (DW /W ))0.356

exchanger with twisted tape is around 235.3% and 67.26% compared to the plain tube and annularly corrugated tube heat exchangers without twisted tapes, respectively. Esmaeilzadeh et al. [41] carried out an experimental study to investigate the heat transfer and friction factor characteristics of γ-Al2O3/water nanofluid in laminar flow regime through plain tube with various thicknesses of twisted tape inserts. Results show that the thicker of twisted tape, the higher convective heat transfer coefficient is. At the same time, the increase of twisted tape thickness leads to increase of friction factor. In addition, the most popularly used correlations for predicting the performance in the corrugated tubes combined with twisted tape were proposed by Zimparov [91,92]. 6.2. Impact of varying length, alternate-axes twisted tapes on the enhancement efficiency With the purpose of achieving a larger enhancement in heat transfer or satisfying a certain operating condition, modified twisted tapes are designed and manufactured in a variety of forms based on the typical ones. These kinds of twisted tape are short length tape with different pitches spaced or manufactured with alternate axes. Most of the related works have been investigated using with experimental methods. Jaisankar et al. [46] carried out a study on the heat transfer and friction factor characteristics of thermo syphon solar water heater with full length Left-Right twist. Twist fitted with rod and spacer at the trailing edge for lengths of 100, 200 and 300 mm for twist ratio. The result shows that the heat transfer performance of the twist fitted with rod and spacer are worse than the full length twist. Friction factor also decreases by 18% and 29% for twist fitted with rod and spacer, respectively. Modified twisted tapes, which have different geometrical progression ratio (GPR) of twists, are experimentally researched by Maddah et al. [57]. The twist ratios changed along the twists with respect to the geometrical progression ratio. Regarding the experimental data, utilization of GPR twists together with nanofluids tends to increase heat transfer and friction factor by 12–52% and 5–28% as compared with the tube with typical twisted tape and nanofluid. From the previous studies, it can be seen that alternate twisted tapes with smaller twisted ratio can offer higher frequencies of flow splits as they possess a large number of alternate points. The twisted tapes with

both uniform and non-uniform alternate lengths (TAs and N-TAs) as well as a typical twisted tape (TT) were comparatively tested by Eiamsa-ard et al. [64]. The result shows that TAs/N-TAs gave better fluid mixing which consequently resulted in higher heat transfer rate. The numerical results indicated that the temperature distributions associated with the uses of TAs were considerably more uniform than that with the use of TT. The experimental results reveal that all the TAs and N-TAs yield higher Nusselt number and friction factor than the TT and the Nusselt number and friction factor obtained are considerably increased with decreasing the alternate length. Heat transfer and friction factor by the N-TAs are discovered to be directly dependent on alternate length rather than the variation of the length. Seemawute et al. [65] experimentally investigated the effect of peripherally-cut twisted tape (PT) with alternate axis (PTA) on the fluid flow and heat transfer enhancement characteristic. The heat transfer rates in the tube fitted with the PTA, PT and TT are respectively improved about 184%, 102% and 57% compared with the plain tube. The maximum thermal performances offered by the PT-A, PT and TT are 1.25, 1.11 and 1.02 at identical pumping power, respectively. The performances of alternate-axes, triangular, rectangular and trapezoidal wings with three different wing-chord ratios of 0.1, 0.2 and 0.3 were investigated by Wongcharee et al. [93]. The alternate-axes were produced by adjusting each plane of twisted tape to 60° difference relative to the adjacent plane. The observation shows that the thermal performance factor given by the twist tape with alternateaxes and trapezoidal wings are higher than those given by the others. Meanwhile, Wongcharee et al. [94] experimentally studied the thermohydraulic characteristics of the circular tubes fitted with alternate clockwise and counterclockwise twisted tape (TA) in the laminar flow regime. In the experiments, the twisted tape with three different twist ratios (Y¼3–5) were inserted individually. The results show that the thermal performance factor (η) increases with increasing Reynolds number. TA offers considerably superior thermal performance factor than that of TT and the performance factor increases with decreasing twist ratio. The thermal performance factors associated by TA at Y¼3, 4 and 5, are respectively 64.4%, 64.2%, and 63.6% higher than those induced by TT at the same twist ratio.

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

6.3. Impact of multiple twisted tapes on the enhancement efficiency The twisted tapes are commonly used in the tube as an individual unit. In order to enhance the heat transfer rate optimally, more than one twist tapes are coupled in a heat exchanger tube, which can in turn induce a stronger vortex motion. With the purpose of gaining an understanding of physical and thermal behavior of the fluid flow in tube with multiple twisted tapes inserted, Hong et al. [59] built up a CFD model of converging–diverging tubes (CDs) equipped with multiple twisted tapes and numerically studied the heat transfer and flow characteristics. The simulation results indicate that both CD and CDT show preferable thermal performance than plain tube at the same pumping power. The increases in the Nusselt number and friction factor for CDT are up to 6.3–35.7% and 1.75–5.3 times of the corresponding CD, respectively. Bhuiya et al. [62] experimentally explored the effects of the double counter twisted tapes on heat transfer and fluid friction characteristics in a heat exchanger tube. The results demonstrated that the Nusselt number, friction factor and thermal enhancement efficiency increase with decreasing twist ratio. In the experimental range of Reynolds number, heat transfer rate and friction factor are obtained about 60–240% and 91–286% higher than those of the plain tube, respectively. Continue to the previous study, Bhuiya et al. [66] investigated the influences of triple twisted tapes on heat transfer rate, friction factor and thermal enhancement efficiency. The experimental results demonstrate that the Nusselt number, friction factor and thermal enhancement efficiency increase with decreasing twist ratio. The Nusselt number and friction factor increase up to 3.85 and 4.2 times compared with the plain tube, respectively. Meanwhile, Zhang et al. [89] numerically studied the heat transfer and flow characteristics in a tube with triple and quadruple twisted tapes. The results are observed that the Nusselt number increase by 171% and 182% by using triple and quadruple twisted tapes, respectively. And the friction factors of the tube fitted with triple and quadruple twisted tapes are about 4.06 and 7.02 times as that of the plain tube. The thermal performance factor of the tubes varies from 1.64 to 2.46. Eiamsa-ard et al. [95] investigated the influences of twincounter (CT)/co-twisted tapes (CoT) (counter/co-swirl tape) on the thermal and physical performance of turbulent flow. For comparison, the experiments also studied the characteristics of single twisted tape (ST) under the similar operation conditions. The experimental results demonstrate that Nusselt number, friction factor and thermal performance factor increase with decrease of twist ratio. The CTs are more efficient than the CoTs for heat transfer enhancement over the range. Heat transfer rates in the tube fitted with the CTs are around 12.5–44.5% and 17.8–50% higher than those with the CoTs and ST, respectively. In addition, the empirical correlations of the heat transfer, friction factor and thermal performance factor were also reported of the ST, CTs and CoTs. The study of dual twisted tape elements in tandem in a heat exchanger tube was also carried out by Eiamsa-ard et al. [96]. Meanwhile, single twisted tape, full-length dual and regularlyspaced dual twisted tapes were studied for comparison. The results indicate that the heat transfer enhancement of the tube fitted with dual twisted tapes is higher than that of the plain tube with/without single twisted tape insert. 6.4. Impact of twisted tapes with fins, winglet on the enhancement efficiency Some additional units such as fins, baffles, etc. combined with the typical twisted tape can be used to achieve higher augmentation compared to smooth twisted tape. For example, the deltawinglet twisted tape is widely studied for its synergy effects of vortex circulation together with secondary flow generated by the

443

delta-winglet part and the main swirl flow produced by twisted tape. Promvonge et al. [43] experimentally investigated the effect of the combined twisted tape and rectangular winglet inserts on heat transfer and pressure drop characteristics for Reynolds number from 4000 to 30,000. The results indicate that the Nusselt number and friction factor for the combined twisted tape and V-winglet increase with increasing winglet to duct height ratios but decreasing winglet pitch to tape width ratios. The thermal performance of using combined vortex-flow devices are approximately 17% higher than the twisted tape individually. Eiamsa-ard et al. [70] experimentally investigated the influence of the twisted tape consisting of centre-wings and alternate-axes (WT-A) on thermohydraulic properties in plain tube. It is also found that the heat transfer rate increases with increasing angle of attack. Meanwhile, the reason of the superior performance of the WT-A have explained as follows: 1. A common swirling flow by the twisted tape; 2. A vortex generated by the wing; 3. A strong collision of the recombined streams behind each alternate point. Following the previous research, Eiamsa-ard et al. [90] comparatively studied the heat transfer enhancement of oblique deltawinglet twisted tape (O-DWT) and straight delta-winglet twisted tape (S-DWT). Delta-winglet twisted is modified by cutting at the edge of the tape with oblique shape and straight shape to produce an O-DWT and S-DWT, respectively. It is found from the result that the mean Nusselt number and friction factor in the tube with the delta-winglet twisted tape increase with decreasing twisted ratio and increasing depth of wing cut ratio. The O-DWT shows higher heat transfer coefficient than the S-DWT. The calculated data shows that the mean Nusselt number and friction factor for the O-DWT are 4.2% and 7.8% higher than those for the S-DWT, respectively. Empirical correlations with the predicted data for Nusselt number and friction factor have been employed for O-DWT and S-DWT. Because of the optimal performance, the DWT can be used to reduce the size of the heat exchanger. In addition, typical delta-winglet tapes were applied as vortex generators to amplify turbulence intensities and produce secondary flows near the surface of tube wall. Thianpong et al. [97] reported the heat transfer and pressure drop characteristics of turbulent flow in tube fitted with perforated twisted tapes with parallel wings (PTT). The design of PTT involves the following concepts: 1. Wings induce an extra turbulence near tube wall and thus efficiently disrupt a thermal boundary layer; 2. Holes existing along a core tube diminish pressure loss within the tube. Compared to the plain tube, the tubes with PTT and TT yielded heat transfer enhancement up to 208% and 190%, respectively. The maximum thermal performance factor is 1.32, which is obtained at Reynolds number of 5500. 6.5. Impact of twisted tapes with slots, holes, cuts on the enhancement efficiency Twisted tape with different geometries can offer different performances and mechanisms of heat transfer enhancement. With the purpose of creating stronger turbulence intensity in the vicinity of tube wall or reducing the pressure drop to a required level, slots, holes, cuts, gaps, etc. are manufactured based on the structure of typical twisted tape.

444

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

Heat transfer and friction factor characteristics in turbulent flow through a tube fitted with perforated twisted tape inserts are experimentally reported by Bhuiya et al. [44]. The Nusselt number, friction factor and thermal performance factor in the tube with perforated twisted tape inserts are discovered to be 110–340, 110– 360 and 28–59% higher than those of the plain tube values, respectively. The influence of porosity 4.5% is more dominant than that of the other porosities of 1.6%, 8.9% and 14.7% in the experimental Reynolds range. That is to say, the porosity of perforated twisted tape is not coordinated with the overall thermal performance of perforated twisted tape. There exists a suitable porosity of twisted tape inserts. Thianpong et al. [45] investigated experimentally the influences of the perforated twisted tape on the heat transfer, pressure drop and thermal performance characteristics. The results reveal that Nusselt number increase with decreasing SP/W and H/W and increasing DP/W, where DP is the diameter of perforation hole, SP is spacing between holes (pitch). For the experimental range, the maximum heat transfer is obtained by utilizing the perforated twisted tape is about 27.4% and 86.7% higher compared with the plain tube with and without typical twisted tape, respectively. Meanwhile, Rahimi et al. [47] experimentally investigated the friction factor, Nusselt number and thermal hydraulic performance of a tube equipped with the classic, perforated, notched and jagged twisted tape inserts. The experiment observation was predicted and explained with numerical method. The results show that the Nusselt number and performance of the jagged insert are higher than other ones and has higher performance at low Reynolds numbers. Compared with the classic twisted tape, the increasing Nusselt number and performance of the jagged insert are up to 31% and 22%, respectively. The higher turbulence intensity of the fluid close to the tube wall has been expressed as the main reason for the experimental observations. Heat transfer augmentation techniques play a vital role for laminar flow heat transfer since the heat transfer coefficient which is in a low level for laminar flow in plain tubes is more need to be enhanced. Murugesan et al. [58] further experimentally studied the enhancement effect of V-cut with different depth and width ratios. The obtained results show that the mean Nusselt number and the mean friction factor in the tube with V-cut twisted tape increase with decreasing twist ratios, width ratios and increasing depth ratios. Eiamsa-ard and Promvonge [67] made an investigation of the effect of twisted tape with serrated-edge insert on heat transfer and pressure loss behaviors. The results present that the heat transfer rate in terms of Nusselt number, Nusselt number increases with the rise in the depth ratio but decreases with raising the width ratio. The heat transfer rate is up to 72.2% and 27% relative to the plain tube and the typical twisted tape inserted tube, respectively. Chang et al. [68,69] devised spiky ribbed twisted tapes with and without edge notches and experimentally studied friction factors and thermal performance factor. The results indicate the present V-notched ribbed spiky twist tapes with forward flows considerably elevate the heat transfer enhancement impacts from the comparative counterparts by bursting the near-wall jets through the notches and initiating the separated vortex system from the spikes and ribs. Salam et al. [75] experimentally studied heat transfer coefficient, friction factor, heat transfer enhancement efficiency in a circular tube fitted with rectangular-cut twisted tape insert. The obtained results show that Nusselt numbers, friction factors and heat transfer enhancement efficiencies increase 2.3–2.9 times, 1.4–1.8 times and 1.9–2.3 compared that of smooth tube, respectively. Turbulent heat transfer and pressure drop in tube fitted with square-cut twisted tape using the water as working fluid were experimentally investigated by Murugesan et al. [76]. The results reveal that heat transfer rate, friction factor and thermal enhancement factor in the

tube equipped with square-cut twisted tape are significantly higher than those fitted with plain twisted tape. The Nusselt number, friction factor and thermal enhancement factor in a tube with square-cut twisted tape are 1.03–1.14, 1.05–1.25 and 1.02–1.06 times of those in tubes with plain twisted tape, respectively. Salman et al. [74,77] numerically investigated the heat transfer and friction factor characteristics of circular tube fitted with classical, quadrant-cut and elliptic-cut twisted tape inserts. The results are presented that there is a notable increase in heat transfer rate and friction factor with decreasing of twist ratio and cut depth. The heat transfer rate and friction factor in the tube fitted with elliptic-cut twist tape are significantly higher than those fitted with classical twist tape. The major experimental findings by Pal et al. [98] are that the twisted tape with oblique teeth in combination with integral spiral rib roughness performs significantly better than the individual enhancement technique acting alone for laminar flow through a circular duct up to a certain value of fin parameter. 6.6. Impact of helical and screw twisted tapes on the enhancement efficiency Different from the previous structural styles, helical and screw twisted tape is further inserts to enhance heat transfer in tube. Patil and Babu [80] carried out a study on the heat transfer and friction factor characteristics through a square duct fitted with helical screw tape of various twist ratios. The experimental results reveal that the Nusselt number increases with the rise of Reynolds number and the reduction of twist ratio. The Nusselt numbers are found to be 3.64–18 and 2.31–6.56 times the plain square. Chougule and Sahu [78] comparatively analyzed the convective heat transfer characteristics of Al2O3/water and CNT/water nanofluids through plain tube in transition regime with helical twisted tape inserts. The experimental results show that the heat transfer performance increases with the increase in the particle volume fraction for both nanofluids. For all the twist ratio of helical screw tape inserts the CNT/water nanofluids with helical screw tape inserts have higher thermal performance and lower pressure drop compared to Al2O3/water nanofluid. 6.7. Impact of center-cleared twisted tapes on the enhancement efficiency In order to achieve good thermo-hydraulic performance, Nanan et al. [49] experimentally researched the heat transfer enhancement of plain tube inserted helically twisted tapes. The results reveal that the employ of counter-helically twisted tapes have higher Nusselt number and friction factor but lower thermal performance factor than that of c-helically twisted tapes under the same conditions. A tape with smaller pitch ratio gives higher Nusselt number and friction factor but lower thermal performance factor. Continue to the research, Nanan et al. [51] reported the influence of different perforated helical twisted tapes (P-HTTs) on the heat transfer, friction drop and thermal performance characteristics. The experimental results reveal that friction loss of P-HTTs is lower compared to that of HTT. Heat transfer, friction loss and thermal performance factor increase with the diameter ratio decreases and the perforation pitch ratio increases. Guo et al. [52] proposed a center-cleared twisted tape. A comparative study between center-cleared twisted tape and the short-width twisted tape was numerically performed in laminar region. The results show that the thermal performance factor of the tube with center-cleared twisted tape can be enhanced by 7–20% and the tubes with short width twisted tape are weakened as compared with the tube with conventional twisted tape, respectively. Thermohydraulics of laminar flow of viscous oil through a circular tube having axial corrugations and fitted with centre-cleared twisted tape was presented by Saha [55]. The major

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

445

Table 6 The comparative characteristic between self-rotating and stationary twisted tapes. No. Author

Name

Working fluid

Condition

Thermal performance factor

Heat transfer enhancement

Flow resistance increment

1

Zhan [30]

Triangular groove twisted tape

Water

1.05–1.35

0.01–0.28 times

0.01–0.68 times

2

Sun [31]

Self-rotating semicircle groove twisted tape

Water

1.04–1.15

0.93–21.28%

1–39.5%

3

Murugesan [76]

Square-cut twisted tape

Water

1.02–1.27

1.40–1.81 times

2.83–3.81 times

4

Water

0.9–1.29

1.2–2.6 times

4–6.15 times

5

Eiamsa-ard [72] Peripherally-cut twisted tape Bhuiya [44] Perforated twisted tape

Air

1.25–1.58

110–340%

110–360%

6

Ou [33]

Self-rotating helical twisted tape

Water

1.063–1.587

14.49–33.04%

20.07–265.74%

7

Nanan [51]

Perforated helical twisted tape

Air

0.95–1.28

150–103.8%

340–430%

8

Nanan [49]

Helical twisted tape

Air

0.85–1.29

1.8–3.3 times

4.1–36.7 times

9

Yin [82]

Self-rotating Jagged twisted tape

Water

1.12–1.4

13.1–74.1%

8.3–35.4%

10

Rahimi [47]

Jagged twisted tape

Water

1.05–1.21

2.49–1.96 times

8.7–6.51 times

11

Lin [21]

Self-rotating polypropylene twisted tape

Water

1.1–1.35

16.04–56.24%

–

12

Eiamsa-ard [72] Stationary twisted tape

Water

0.87–1.01

1.3–1.7 times

3–4.2 times

13

Liu [32]

Water

1–1.5

16.17–22.53%

0.2–0.46 times

14

0.8–0.98

22.6–56.8%

1.63–3.22 times

15

Eiamsa-ard [81] Regularly spaced twisted tape Bhuiya [66] Triple twisted tape inserts

Air

1.1–1.44

1.73–3.85 times

1.91–4.2 times

16

Eiamsa-ard [63] Twin-counter twisted tapes

Water

1.01–1.39

17

Eiamsa-ard [63] Twin co-twisted tapes

Water

0.89–1.1

12.5–44.5% compared to twin co-twisted tapes –

26.5–45.5% compared to twin co-twisted tapes –

18

Promvonge [43] Twisted tape with winglet vortex generators

Air

1.2–1.62

1.91–3.03 times

3.94–9.44 times

19

Thianpong [97]

0.91–1.32

0.5–1.9 times

6–12 times

20

Zhai [28]

1–1.39

0.28–0.56 times

5 times

21

Eiamsa-ard [71] Circular-rings and twisted tape

Air

1–1.42

2.5–4.5 times

9–33.8 times

22

Murugesan [50] Twisted tape consisting of wire-nails

Water

Re¼6000– 55,000 Y ¼5–7 Re¼5000– 45,000 Y ¼5–7 Re¼2000–12,000 Y ¼2–6 Re¼5000–12,000 Y ¼3 Re¼7200–49,800 Y ¼1.92 Rp ¼1.6–14.7%. Re¼5000– 55,000 Y ¼2–4 Re¼6000– 20,000 Y ¼3 Re¼6000– 20,000 Y ¼3 Re¼8000– 60,000 Y ¼5–7 Re¼2950–11,800 Y ¼5–7 Re¼5000– 65,000 Y ¼4–7 Re¼5000–12,000 Y ¼3 Re¼8000– 65,000 Y ¼4–6 Re¼5500–11,000 Y ¼6–8 Re¼7200–50,200 Y ¼1.92–6.79 Re¼3700–21,000 Y ¼2.5–4 Re¼3700–21,000 Y ¼2.5–4 Re¼4000– 30,000 Y ¼4–5 Re¼5500–20,500 Y ¼3 Re¼15,000– 55,000 Re¼6000– 20,000 Y ¼3–5 Re¼2000–12,000 Y ¼2–6

1.06–1.33

1.47–1.98 times

3.22–4.26 times

Self-rotating regularly spaced twisted tape

Air

Perforated twisted tape with Water parallel wings Miniature hydraulic turbine Water

findings of this experimental investigation are that the centrecleared twisted tapes in combination with axial corrugation perform better than the individual enhancement technique acting alone for laminar flow through a circular duct up to a certain amount of centre clearance. Pal et al. [53] experimentally studied the friction factor and Nusselt number data for laminar flow through a circular duct having integral transverse corrugation and fitted with center cleared twisted tape. It is found that the center cleared twisted tapes in combination with integral transverse corrugation perform better than the individual enhancement technique acting alone for laminar flow through a circular duct up to a certain amount of twisted tape center clearance. The experimental friction factor and Nusselt number data for laminar flow through a circular duct fitted

with centre-cleared twisted tape were presented by Bhattacharyya et al. [54,56]. The results show that the centre-cleared twisted tapes in combination with integral helical rib roughness perform significantly better than the individual enhancement technique acting alone for laminar flow through a circular duct up to a certain amount of twisted tape centre-clearance. 6.8. Impact of tapes with other kinds of modifications on the enhancement efficiency With the development of the research, other kinds of modified twisted tapes have been presented by researchers. Twisted tape equipped with other kinds of devices such as metal nail can also achieve high heat transfer efficiency as a compound heat transfer

446

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

augmentation. Murugesan et al. [50] experimentally investigate the performance of a double pipe heat exchanger equipped with twisted tape consisting wire nails (WN-TT). The vortex generation by the attached wire nail on twisted tape plays a vital role for the higher heat transfer rate of WN-TT. The main reason of the better comprehensive effect as follows: 1. Small wire nails on the tape produce the additional disturbance of turbulence in the flow; 2. Main swirl flow generated by P-TT. The disturbance in the flow path is higher in the WN-TT than the tube fitted with square-cut twisted tape (S-TT) and plain tube twisted tape (P-TT). Therefore, the WN-TT can be used in place P-TT and S-TT with the purpose of reducing the size of heat exchanger. Eiamsa-ard et al. [71] reported thermohydraulics of turbulent flow through heat exchanger tubes fitted with circular-rings and twisted tape. The heat transfer rate, friction factor and thermal performance factor of the combined circular-ring turbulators and twisted tape are considerably higher than those of CRT alone. For the range examined, the increases of mean Nusselt number, friction factor and thermal performance, in the tube equipped with combined devices, respectively, are 25.8%, 82.8% and 6.3% over those in the tube with the CRT alone. The major reason of the dissipation of dynamic pressure as follows: 1. The flow obstruction of circular-ring and twisted tape. 2. The reverse, separation and swirl flows induced by the devices. 3. The increase of flow contact area. Eiamsa-ard et al. [81] experimentally and numerically investigated the heat exchanger tube equipped regularly-spaced twisted tapes. The results present that heat transfer rate and friction increased with decreasing twist ratio and space ratio. Full length twisted tapes (Y¼6.0 and 8.0) have the higher heat transfer rate, friction factor and thermal performance factor than regularly-spaced twisted tapes at similar conditions. Hong et al. [99] found that the heat transfer efficiency index of a converging–diverging tube with evenly spaced twisted tapes is 0.85–1.21 and 1.07–1.15 compared to that of a smooth circular tube and a converging–diverging tube

without twisted tape inserts, respectively. Short-length twisted tapes are popularly studied by scholars in recent years [100–103]. It is found that the tube with short-length twisted tapes consistently yields higher local Nusselt number than that the one without swirl generator. The local Nusselt numbers decrease with increasing axial distance due to the decaying effect. The visualization of flow structure in the tubes with short-length twisted tapes is also presented by Eiamsa-ard et al. [100].

7. Discussion Twisted tapes as one of the most important passive heat transfer technique have been experimentally and numerically investigated by many researchers in recent years. This paper divides twisted tapes into two categories: self-rotating twisted tapes and stationary twisted tapes. An overview of existing researches in each category is presented. The stationary twisted tapes can generate the swirl flow in the fluid flow in heat exchanger tube, which can enhance the flow turbulence intensity, and lead to better convection heat transfer compared to the plain tube with an axial flow. The self-rotating twisted tapes can strengthen the heat transfer efficiency and achieve on-line automatic anti-scaling and descaling effect. The self-rotating twisted tapes change the direction of fluid flow, form a rotational flow, get the bulk flow and fluid at the tube surface mixed and disrupt the development of boundary layer. Compared with the stationary twisted tapes, the self-rotating twisted tapes have the dual effect for heat exchanger. The comparative characteristics between self-rotating and stationary twisted tapes for present test tubes are presented in Table 6, which are created by various Y between 2 and 8 in turbulent flow region. It is found that the thermal performance factor decreases with the increasing of Re and Y, respectively. The thermal performance factor comparisons of twisted tapes in turbulent flow are shown in Fig. 5. It can be concluded that all the selfrotating twisted tapes have higher thermal performance factor than the same kind stationary twisted tape. The thermal performance factor of tube fitted with self-rotating helical twisted tape varies between 1.063 and 1.587, which is much higher than those

Fig. 5. The thermal performance factor comparisons of twisted tapes in turbulent region and Y range of 2–8.

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

of other self-rotating twisted tapes. Twisted tapes with other combined device obtain high thermal performance factor than stationary smooth twisted tape. Twisted tape with winglet vortex generators achieves the highest thermal performance factor in the present stationary twisted tapes. Tubes equipped with self-rotating polypropylene twisted tape have much higher thermal performance factor than those of stationary aluminum twisted tape. That is to say, the material property of twisted tape has important influence on the thermal performance. The material property should be considered while choosing the type of twisted tape. It is difficult to decide which kind of twisted tape is the best one, because different kinds of twisted tapes perform differently in various situations. The combination approach has been attempted to leverage the strengths of different kinds of twisted tape. This approach is able to enhance the heat transfer, as well as increase the pressure drop. To achieve an optimal thermal performance with twisted tape fitted in the tube, an appropriate twisted tape modification is necessary for heat transfer enhancement with pressure loss at a reasonable level.

8. Conclusion This paper provides an overview of self-rotating and stationary twisted tapes. The thermal characteristic, anti-fouling and descaling performances of self-rotating twisted tapes compared to stationary twisted tapes have been comprehensively discussed. The influences of structure parameters on the performance have been comparatively analyzed. The conclusions of this paper are listed as follows: 1. Compared with the stationary twisted tapes, the heat transfer enhancement and the function of online anti-scaling and descaling can be obtained with the self-rotating inserts in tube. Meanwhile, the tube with self-rotating twisted tapes gives the lower pressure drop in the researches. 2. The twisted tapes achieve remarkable and effective characterizes in laminar regions than in turbulent regions. Meanwhile, the twisted tapes have significant performance both in common fluid and nanofluid. 3. The Nusselt number and friction factor in the tube with cut twisted tape increase with decreasing twist ratios, width ratios and increasing depth ratios. The heat transfer and friction factor increases with decreasing the twist ratio and the width of twisted tape. The performance factors of all twisted tapes tend to decrease with increasing Reynolds number. 4. The novel twisted tapes can achieve an optimal comprehensive performance compared with the typical twisted tape, for the former can offer a stronger swirl flow to provide superior mixing and more efficient interruption of thermal boundary layer or have the access to prevent the formation of higher pressure drop. 5. The major criterion for selecting superior twisted tape configurations is the high value of thermal performance factor. All of these selected modified schemes have better thermal performance factor than typical twisted tape. The values of selfrotating twisted tape are higher than stationary twisted tapes. 6. The twisted tape, which is relevant to minimum pressure drop conjugate with the maximum heat transfer rate, is the optimal shape. At the same time, the method of twisted tape combined with other techniques is the new development direction of heat transfer enhancement.

Acknowledgment This research is financially supported by the financial support from the Science and Technology Key Project of Henan Province

447

(142102210494) and National Natural Science Foundation of China (21576245). We acknowledge their support and assistance in this research.

References [1] Qi Z. Advances on air conditioning and heat pump system in electric vehicles – a review. Renew Sustain Energy Rev 2014;38:754–64. [2] Tuo H, Hrnjak P. Flash gas bypass in mobile air conditioning system with R134a. Int J Refrig 2012;35:1869–77. [3] Yu L, Liu D. Study of the thermal effectiveness of laminar forced convection of nanofluids for liquid cooling applications. IEEE Trans Compon Packag Manuf Technol 2013;3:1693–704. [4] Tuo H. Thermal-economic analysis of a transcritical Rankine power cycle with reheat enhancement for a low-grade heat source. Int J Energy Res 2013;37:857–67. [5] Tuo H, Hrnjak P. Effect of the header pressure drop induced flow maldistribution on the microchannel evaporator performance. Int J Refrig 2013;36:2176–86. [6] Zhang C, Li Y, Wang L, Xu K, Wu J. Review heat exchanger: research development of self-rotating inserts in heat exchanger tubes. Int J Eng Trans A: Basics 2014;27:1503–10. [7] Zhang C, Wang D, Zhu Y, Han Y, Wu J, Peng X. Numerical study on heat transfer and flow characteristics of a tube fitted with double spiral spring. Int J Therm Sci 2015;94:18–27. [8] Saha S, Saha SK. Enhancement of heat transfer of laminar flow through a circular tube having integral helical rib roughness and fitted with wavy strip inserts. Exp Therm Fluid Sci 2013;50:107–13. [9] Anvari AR, Lotfi R, Rashidi AM, Sattari S. Experimental research on heat transfer of water in tubes with conical ring inserts in transient regime. Int Commun Heat Mass 2011;38:668–71. [10] Anvari AR, Javaherdeh K, Emami-Meibodi M, Rashidi AM. Numerical and experimental investigation of heat transfer behavior in a round tube with the special conical ring inserts. Energy Convers Manag 2014;88:214–7. [11] Zhang Z, Yang W, Guan C, Ding Y, Li F, Yan H. Heat transfer and friction characteristics of turbulent flow through plain tube inserted with rotorassembled strands. Exp Therm Fluid Sci 2012;38:33–9. [12] Liu S, Sakr M. A comprehensive review on passive heat transfer enhancements in pipe exchangers. Renew Sustain Energy Rev 2013;19:64–81. [13] Hasanpour A, Farhadi M, Sedighi K. A review study on twisted tape inserts on turbulent flow heat exchangers: the overall enhancement ratio criteria. Int Commun Heat Mass 2014;55:53–62. [14] Lin Q, Lin J, Lin R. Study on the rotating speed of self-rotating twisted tape inserted tubes. Chin J Mech Eng (Engl Ed) 2007;18:1970–3. [15] Li J. Experimental study on the working characteristics of built-in aluminum self-rotating twisted tape heat exchanger tube. Guangxi University; 2006. [16] Zhang L, Qian H, Xuan Y, Yu X. Numerical simulation of the three dimensional fluid flow and heat transfer of heat exchanger tubes with twisted tape insert. Chin J Mech Eng (Engl Ed) 2005;41:66–70. [17] Zhang L, Qian H, Yu X, Xuan Y. Heat transfer enhancement of heat exchanger tubes with rotating twisted tape insert. Chin J Mech Eng (Engl Ed) 2007;43:139–43. [18] Zhang L. Investigation on enhanced heat transfer mechanism and cleaning synamics of the rotating twisted tape. Nanjing University of Science & Technology; 2006. [19] Feng ZF, Sun RJ, Lin QY. Numerical simulation of pressure drop characteristics in a circular tube with self-rotating twisted tape inserts. J Chin Guangxi Univ (Nat Sci Ed) 2013:657–62. [20] Wang J. Experimental research on heat transfer and flow resistance of upward-low heat transfer tube with self-rotating aluminum twisted tapes. Guangxi University; 2008. [21] Lin H. Study on the working characteristics and heat transfer enhancement of the polypropylene self-rotating twisted tape in side vertical heat exchanger tube. Guangxi University; 2007. [22] Yu X, Yu T, Peng D. Twisted strip with oblique teeth to efficiently remove fouling and enhance heat transfer at low flowing velocity. Chin J Chem Eng 2005:750–3. [23] Peng D, Liu G, Yu X. New straight strip-insert with elliptical teeth and broken edge for removing fouling and enhancing heat transfer. Chin J Eng Des 2006:392–5. [24] Lin Q, Lin R, Feng Q. Study on the miniature hydraulic turbine in the heat exchanger tube. Chin J Mech Eng (Engl Ed) 2001;37:41–3. [25] Lin J, Lin Q, Lin R. Rotating speed calculation for hydraulic turbine inside heat exchanger tubes. Chin J Mech Eng (Engl Ed) 2008;44:105–11. [26] Lin Q, Lin R, Li P. Experimental study on the primary structural parameters of self-antifouling hydraulic turbine inside heat exchanger tube. Chin J Mech Eng (Engl Ed) 2004;15:346–8. [27] Lin Q, Li P, Lin R. Study on the heat transfer enhancement by the hydraulic turbine in a tube. Chin J Mech Eng (Engl Ed) 2004;40:165–9. [28] Zhai L. Study on the performance of built-in miniature hydraulic turbine heat exchanger tube. Guangxi University; 2004.

448

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

[29] Zhan S. Study on experiment and numerical simulation of flow field in a heat exchanger tube fitted with triangular groove twisted tape insert. Guangxi University; 2012. [30] Zhan S, Lin Q, Feng Z. Rotational and resistance characteristics in a circular tube fitted with triangular groove twisted-tape insert. Chin J Chem Equip Technol 2012;33:36–9. [31] Sun R. Experiment and simulation of heat transfer enhancement in a circular tube fitted with semicircle groove twisted tape. Guangxi University; 2013. [32] Liu X. Experimental study of the heat transfer enhancement in a downingchannel tube fitted with regularly spaced twisted tape and coiled. Guangxi University; 2014. [33] Ou X. Experimental studies on working characteristics of helically twisted tape and numerical simulation analysis in vertical heat exchanger tube. Guangxi University; 2014. [34] Azmi WH, Sharma KV, Sarma PK, Mamat R, Anuar S. Comparison of convective heat transfer coefficient and friction factor of TiO2 nanofluid flow in a tube with twisted tape inserts. Int J Therm Sci 2014;81:84–93. [35] Kanizawa FT, Mogaji TS, Ribatski G. Evaluation of the heat transfer enhancement and pressure drop penalty during flow boiling inside tubes containing twisted tape insert. Appl Therm Eng 2014;70:328–40. [36] Mogaji TS, Kanizawa FT, Bandarra Filho EP, Ribatski G. Experimental study of the effect of twisted-tape inserts on flow boiling heat transfer enhancement and pressure drop penalty. Int J Refrig 2013;36:504–15. [37] Bas H, Ozceyhan V. Heat transfer enhancement in a tube with twisted tape inserts placed separately from the tube wall. Exp Therm Fluid Sci 2012;41:51–8. [38] Song S, Liao Q, Shen W. Laminar heat transfer and friction characteristics of microencapsulated phase change material slurry in a circular tube with twisted tape inserts. Appl Therm Eng 2013;50:791–8. [39] Mokkapati V, Lin C. Numerical study of an exhaust heat recovery system using corrugated tube heat exchanger with twisted tape inserts. Int Commun Heat Mass Transf 2014;57:53–64. [40] Azmi WH, Sharma KV, Sarma PK, Mamat R, Anuar S, Syam Sundar L. Numerical validation of experimental heat transfer coefficient with SiO2 nanofluid flowing in a tube with twisted tape inserts. Appl Therm Eng 2014;73:296–306. [41] Esmaeilzadeh E, Almohammadi H, Nokhosteen A, Motezaker A, Omrani AN. Study on heat transfer and friction factor characteristics of γ-Al2O3/water through circular tube with twisted tape inserts with different thicknesses. Int J Therm Sci 2014;82:72–83. [42] Kanizawa FT, Ribatski G. Two-phase flow patterns and pressure drop inside horizontal tubes containing twisted-tape inserts. Int J Multiph Flow 2012;47:50–65. [43] Promvonge P, Suwannapan S, Pimsarn M, Thianpong C. Experimental study on heat transfer in square duct with combined twisted-tape and winglet vortex generators. Int Commun Heat Mass Transf 2014;59:158–65. [44] Bhuiya MMK, Chowdhury MSU, Saha M, Islam MT. Heat transfer and friction factor characteristics in turbulent flow through a tube fitted with perforated twisted tape inserts. Int Commun Heat Mass Transf 2013;46:49–57. [45] Thianpong C, Eiamsa-ard P, Eiamsa-ard S. Heat transfer and thermal performance characteristics of heat exchanger tube fitted with perforated twisted-tapes. Heat Mass Transf 2012;48:881–92. [46] Jaisankar S, Radhakrishnan TK, Sheeba KN, Suresh S. Experimental investigation of heat transfer and friction factor characteristics of thermosyphon solar water heater system fitted with spacer at the trailing edge of Left–Right twisted tapes. Energy Convers Manag 2009;50:2638–49. [47] Rahimi M, Shabanian SR, Alsairafi AA. Experimental and CFD studies on heat transfer and friction factor characteristics of a tube equipped with modified twisted tape inserts. Chem Eng Process: Process Intensif 2009;48:762–70. [48] Sivashanmugam P, Nagarajan PK. Studies on heat transfer and friction factor characteristics of laminar flow through a circular tube fitted with right and left helical screw-tape inserts. Exp Therm Fluid Sci 2007;32:192–7. [49] Nanan K, Yongsiri K, Wongcharee K, Thianpong C, Eiamsa-ard S. Heat transfer enhancement by helically twisted tapes inducing co- and counterswirl flows. Int Commun Heat Mass Transf 2013;46:67–73. [50] Murugesan P, Mayilsamy K, Suresh S. Heat transfer and friction factor studies in a circular tube fitted with twisted tape consisting of wire-nails. Chin J Chem Eng 2010;18:1038–42. [51] Nanan K, Thianpong C, Promvonge P, Eiamsa-ard S. Investigation of heat transfer enhancement by perforated helical twisted-tapes. Int Commun Heat Mass Transf 2014;52:106–12. [52] Guo J, Fan A, Zhang X, Liu W. A numerical study on heat transfer and friction factor characteristics of laminar flow in a circular tube fitted with centercleared twisted tape. Int J Therm Sci 2011;50:1263–70. [53] Pal S, Saha SK. Laminar flow and heat transfer through a circular tube having integral transverse corrugations and fitted with centre-cleared twisted-tape. Exp Therm Fluid Sci 2014;57:388–95. [54] Bhattacharyya S, Saha S, Saha SK. Laminar flow heat transfer enhancement in a circular tube having integral transverse rib roughness and fitted with centre-cleared twisted-tape. Exp Therm Fluid Sci 2013;44:727–35. [55] Saha SK. Thermohydraulics of laminar flow of viscous oil through a circular tube having axial corrugations and fitted with centre-cleared twisted-tape. Exp Therm Fluid Sci 2012;38:201–9. [56] Bhattacharyya S, Saha SK. Thermohydraulics of laminar flow through a circular tube having integral helical rib roughness and fitted with centrecleared twisted-tape. Exp Therm Fluid Sci 2012;42:154–62.

[57] Maddah H, Alizadeh M, Ghasemi N, Wan Alwi SR. Experimental study of Al2O3/water nanofluid turbulent heat transfer enhancement in the horizontal double pipes fitted with modified twisted tapes. Int J Heat Mass Transf 2014;78:1042–54. [58] Murugesan P, Mayilsamy K, Suresh S, Srinivasan PSS. Heat transfer and pressure drop characteristics in a circular tube fitted with and without V-cut twisted tape insert. Int Commun Heat Mass Transf 2011;38:329–34. [59] Hong Y, Deng X, Zhang L. 3D numerical study on compound heat transfer enhancement of converging–diverging tubes equipped with twin twisted tapes. Chin J Chem Eng 2012;20:589–601. [60] Promvonge P, Pethkool S, Pimsarn M, Thianpong C. Heat transfer augmentation in a helical-ribbed tube with double twisted tape inserts. Int Commun Heat Mass Transf 2012;39:953–9. [61] Eiamsa-ard S, Wongcharee K. Heat transfer characteristics in micro-fin tube equipped with double twisted tapes: effect of twisted tape and micro-fin tube arrangements. J Hydrodyn, Ser. B 2013;25:205–14. [62] Bhuiya MMK, Sayem ASM, Islam M, Chowdhury MSU, Shahabuddin M. Performance assessment in a heat exchanger tube fitted with double counter twisted tape inserts. Int Commun Heat Mass Transf 2014;50:25–33. [63] Eiamsa-ard S, Thianpong C, Eiamsa-ard P. Turbulent heat transfer enhancement by counter/co-swirling flow in a tube fitted with twin twisted tapes. Exp Therm Fluid Sci 2010;34:53–62. [64] Eiamsa-ard S, Somkleang P, Nuntadusit C, Thianpong C. Heat transfer enhancement in tube by inserting uniform/non-uniform twisted-tapes with alternate axes: effect of rotated-axis length. Appl Therm Eng 2013;54:289– 309. [65] Seemawute P, Eiamsa-ard S. Thermohydraulics of turbulent flow through a round tube by a peripherally-cut twisted tape with an alternate axis. Int Commun Heat Mass Transf 2010;37:652–9. [66] Bhuiya MMK, Chowdhury MSU, Shahabuddin M, Saha M, Memon LA. Thermal characteristics in a heat exchanger tube fitted with triple twisted tape inserts. Int Commun Heat Mass Transf 2013;48:124–32. [67] Eiamsa-ard S, Promvonge P. Thermal characteristics in round tube fitted with serrated twisted tape. Appl Therm Eng 2010;30:1673–82. [68] Chang SW, Guo MH. Thermal performances of enhanced smooth and spiky twisted tapes for laminar and turbulent tubular flows. Int J Heat Mass Transf 2012;55:7651–67. [69] Chang SW, Huang BJ. Thermal performances of tubular flows enhanced by ribbed spiky twist tapes with and without edge notches. Int J Heat Mass Transf 2014;73:645–63. [70] Eiamsa-ard S, Wongcharee K, Eiamsa-ard P, Thianpong C. Thermohydraulic investigation of turbulent flow through a round tube equipped with twisted tapes consisting of centre wings and alternate-axes. Exp Therm Fluid Sci 2010;34:1151–61. [71] Eiamsa-ard S, Kongkaitpaiboon V, Nanan K. Thermohydraulics of turbulent flow through heat exchanger tubes fitted with circular-rings and twisted tapes. Chin J Chem Eng 2013;21:585–93. [72] Eiamsa-ard S, Seemawute P, Wongcharee K. Influences of peripherally-cut twisted tape insert on heat transfer and thermal performance characteristics in laminar and turbulent tube flows. Exp Therm Fluid Sci 2010;34:711–9. [73] Lei Y, Zhao C, Song C. Enhancement of turbulent flow heat transfer in a tube with modified twisted tapes. Chem Eng Technol 2012;35:2133–9. [74] Salman SD, Kadhum AAH, Takriff MS, Mohamad AB. CFD analysis of heat transfer and friction factor characteristics in a circular tube fitted with quadrant-cut twisted tape inserts. Math Probl Eng 2013;2013:1–08. [75] Salam B, Biswas S, Saha S, Bhuiya MMK. Heat transfer enhancement in a tube using rectangular-cut twisted tape insert. Procedia Eng 2013;56:96–103. [76] Murugesan P, Mayilsamy K, Suresh S. Turbulent heat transfer and pressure drop in tube fitted with square-cut twisted tape. Chin J Chem Eng 2010;18:609–17. [77] Salman SD, Kadhum AAH, Takriff MS, Mohamad AB. CFD simulation of heat transfer and friction factor augmentation in a circular tube fitted with elliptic-cut twisted tape inserts. Math Probl Eng 2013;2013:1–07. [78] Chougule SS, Sahu SK. Heat transfer and friction characteristics of Al2O3/ water and CNT/water nanofluids in transition flow using helical screw tape inserts-a comparative study. Chem Eng Process: Process Intensif 2015;88:78–88. [79] Suresh S, Venkitaraj KP, Selvakumar P, Chandrasekar M. A comparison of thermal characteristics of Al2O3/water and CuO/water nanofluids in transition flow through a straight circular duct fitted with helical screw tape inserts. Exp Therm Fluid Sci 2012;39:37–44. [80] Patil S, Vijay Babu P. Experimental heat transfer and friction factor studies through a square duct fitted with helical screw tapes. Can J Chem Eng 2014;92:663–70. [81] Eiamsa-ard P, Piriyarungroj N, Thianpong C, Eiamsa-ard S. A case study on thermal performance assessment of a heat exchanger tube equipped with regularly-spaced twisted tapes as swirl generators. Case Stud Therm Eng 2014;3:86–102. [82] Yin S, Lin Q, Liu M. Study of flow resistance and heat transfer characteristics of heat transfer tube with inner-setting jagged twisted-tape. Chin J Light Ind Mach 2011;29:22–6. [83] Li Q, Chen D, Xiang Y. Crystallized salty in heat transfer tube spiral rotation cleaning technology study. J Therm Sci Tech – Jpn 2008;7:217–20. [84] Zhang Lin Yu Y, Qian H. Experimental research of self-preventing fouling technology for the self-rotating twisted tape in heat exchangers. Chin J Chem Eng 2006;34(3):16–9.

C. Zhang et al. / Renewable and Sustainable Energy Reviews 53 (2016) 433–449

[85] Yu X, Yu T, Peng D, Jiang S, Luo J. Twisted strip with oblique teeth to efficiently remove fouling and enhance heat transfer at low flowing velocity. Chin J Chem Ind Eng 2005;56(4):750–3. [86] Yu T, Yu X, Zhi X, Jiang S, Liu G, Peng D. Research on the twisted strip with teeth to enhance self-cleaning ability of heat transfer tubes at low flowing velocity. Chin J Xiangtan Univ 2004:89–91. [87] Thianpong C, Eiamsa-ard P, Wongcharee K, Eiamsa-ard S. Compound heat transfer enhancement of a dimpled tube with a twisted tape swirl generator. Int Commun Heat Mass Transf 2009;36:698–704. [88] Naphon P. Heat transfer and pressure drop in the horizontal double pipes with and without twisted tape insert. Int Commun Heat Mass Transf 2006;33:166–75. [89] Zhang X, Liu Z, Liu W. Numerical studies on heat transfer and flow characteristics for laminar flow in a tube with multiple regularly spaced twisted tapes. Int J Therm Sci 2012;58:157–67. [90] Eiamsa-ard S, Wongcharee K, Eiamsa-ard P, Thianpong C. Heat transfer enhancement in a tube using delta-winglet twisted tape inserts. Appl Therm Eng 2010;30:310–8. [91] Zimparov V. Prediction of friction factors and heat transfer coefficients for turbulent flow in corrugated tubes combined with twisted tape inserts. Part 1: Friction factors. Int J Heat Mass Transf 2004;47:589–99. [92] Zimparov V. Prediction of friction factors and heat transfer coefficients for turbulent flow in corrugated tubes combined with twisted tape inserts. Part 2: Heat transfer coefficients. Int J Heat Mass Transf 2004;47:385–93. [93] Wongcharee K, Eiamsa-ard S. Heat transfer enhancement by twisted tapes with alternate-axes and triangular, rectangular and trapezoidal wings. Chem Eng Process: Process Intensif 2011;50:211–9. [94] Wongcharee K, Eiamsa-ard S. Friction and heat transfer characteristics of laminar swirl flow through the round tubes inserted with alternate clockwise and counter-clockwise twisted-tapes. Int Commun Heat Mass Transf 2011;38:348–52.

449

[95] Eiamsa-ard S, Promvonge P. Performance assessment in a heat exchanger tube with alternate clockwise and counter-clockwise twisted-tape inserts. Int J Heat Mass Transf 2010;53:1364–72. [96] Eiamsa-ard S, Thianpong C, Eiamsa-ard P, Promvonge P. Thermal characteristics in a heat exchanger tube fitted with dual twisted tape elements in tandem. Int Commun Heat Mass transf 2010;37:39–46. [97] Thianpong C, Eiamsa-ard P, Promvonge P, Eiamsa-ard S. Effect of perforated twisted-tapes with parallel wings on heat transfer enhancement in a heat exchanger tube. Energy Procedia 2012;14:1117–23. [98] Pal PK, Saha SK. Experimental investigation of laminar flow of viscous oil through a circular tube having integral spiral corrugation roughness and fitted with twisted tapes with oblique teeth. Exp Therm Fluid Sci 2014;57:301–9. [99] Hong M, Deng X, Huang K, Li Z. Compound heat transfer enhancement of a converging-diverging tube with evenly spaced twisted-tapes. Chin J Chem Eng 2007;15:814–20. [100] Eiamsa-ard S, Thianpong C, Eiamsa-ard P, Promvonge P. Convective heat transfer in a circular tube with short-length twisted tape insert. Int Commun Heat Mass Transf 2009;36:365–71. [101] Arment TW, Todreas NE, Bergles AE. Critical heat flux and pressure drop for tubes containing multiple short-length twisted-tape swirl promoters. Nucl Eng Des 2013;257:1–11. [102] Eiamsa-ard S, Seemawute P. Decaying swirl flow in round tubes with shortlength twisted tapes. Int Commun Heat Mass Transf 2012;39:649–56. [103] Ferroni P, Block RE, Todreas NE, Bergles AE. Experimental evaluation of pressure drop in round tubes provided with physically separated, multiple, short-length twisted tapes. Exp Therm Fluid Sci 2011;35:1357–69.