Rheological behaviour of nanofluids: A review

Renewable and Sustainable Energy Reviews 53 (2016) 779–791

Contents lists available at ScienceDirect

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

Rheological behaviour of nanofluids: A review Anuj Kumar Sharma a,n, Arun Kumar Tiwari b, Amit Rai Dixit a a b

Department of Mechanical Engineering, Indian School of Mines, Dhanbad 826004, India Department of Mechanical Engineering, Institute of Engineering & Technology, GLA University, Mathura 281406, India

art ic l e i nf o

a b s t r a c t

Article history: Received 1 October 2014 Received in revised form 30 June 2015 Accepted 17 September 2015

A colloidal mixture of nanometre-sized (o 100 nm) metallic and non-metallic particles in conventional fluid is called nanofluid. Nanofluids are considered to be potential heat transfer fluids because of their superior thermal and tribological properties. In recent period, nanofluids have been the focus of attention of the researchers. This paper presents a summary of a number of important research works that have been published on rheological behaviour of nanofluids. This review article not only discusses the influence of particle shape and shear rate range on rheological behaviour of nanofluids but also studies other factors affecting the rheological behaviour. These other factors include nanoparticle type, volumetric concentration in different base fluids, addition of surfactant and externally applied magnetic field. From the literature review, it has been found that particle shape, its concentration, shear rate range, surfactant and magnetic field significantly affect the rheological behaviour of any nanofluid. It has been observed that nanofluids containing spherical nanoparticles are more likely to exhibit Newtonian behaviour and those containing nanotubes show non-Newtonian flow behaviour. Furthermore, nanofluids show Newtonian behaviour at low shear rate values while behave as non-Newtonian fluid at high shear rate values. Authors have also identified the inadequacies in the research works so far which require further investigations. & 2015 Elsevier Ltd. All rights reserved.

Keywords: Nanofluids Nanoparticles Rheological behaviour Newtonian Non-Newtonian Viscosity Pressure drop

Contents 1. 2.

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rheological behaviour of nanofluids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1. Newtonian and non-Newtonian behaviour of nanofluids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2. Rheological behaviour of ferrofluids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3. Effect of surfactants on rheological behaviour of nanofluids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Recommendations for future work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

779 786 786 786 786 786 789 789

1. Introduction

Abbreviations: ASCH, Al2O3–SiO2 clay hybrid; BCA, 2-Butoxyethylacetate; CA, Diethylene glycol monethyl ether acetate; CMC, Carboxy methyl cellulose; CNT, Carbon nanotube; DEG, Diethylene glycol; EG, Ethylene glycol; GNP, Graphene nanoplatelets; HTPB, Hydranxy terminated polybutadiene; ITO, Indium Tin Oxide; ICH, Iron oxide clay hybrid; MWCNT, Multi walled carbon nanotube; PG, Propylene glycol; PPG, Poly propylene glycol; PSi, Poly siloxane; TNT, Titanate nanotube n Corresponding author. Tel.: þ 91 9711037075; fax: þ 91 5422368157 E-mail address: [email protected] (A.K. Sharma). http://dx.doi.org/10.1016/j.rser.2015.09.033 1364-0321/& 2015 Elsevier Ltd. All rights reserved.

Conventional fluids, such as, mineral oils, have excellent lubrication properties but poor thermal properties that restrict their use as coolants in industrial applications. Nowadays a number of methods are available to enhance the heat transfer rate of any conventional fluid. One such method may be the addition of small-sized solid particles (millimetre and micrometre) in conventional fluid that can improve its thermal properties. But use of these fluids has shown serious problems such as clogging, high erosion, pressure drop in pipelines and poor stability of

780

A.K. Sharma et al. / Renewable and Sustainable Energy Reviews 53 (2016) 779–791

suspension. About a decade ago, nanometre-sized particles replaced these milli- and micro-sized particles in the suspension, leading to the development of a new class of fluids called ‘nanofluids’. These nanofluids have a number of advantages, such as, better stability, greater thermal conductivity and lower pressure drop compared to the base fluid. Also, use of these nanofluids has shown a remarkable improvement of performance parameters in machining, such as, milling [1–8], grinding [9–18], drilling [19] and turning [20–23] of various metals and their alloys. Sharma et al. [24] reviewed the literature available on nanofluid application in various machining processes as cutting fluid and observed that nanofluid improved machining performance significantly. Nanofluids are colloidal mixtures of nanometre-sized particles (1–100 nm) in a base fluid. The nanoparticles can be metallic, nonmetallic, oxide, carbide, ceramics, carbonic, mixture of different nanoparticles (hybrid nanoparticles) and even nanoscale liquid droplets. The base fluid may be a low viscous liquid like water, refrigerant or a high viscous liquid like ethylene glycol, mineral oil or a mixture of different types of liquids (EG þwater, waterþpropylene glycol etc.). The term ‘nanofluid’ was first coined by Dr. Stephen Choi (Energy Technology Division, Argonne National Laboratory, USA) in 1995 [25]. However, there was an earlier and independent report by Masuda et al. [26] which dealt with the similar subject. At the initial stage, research on nanofluids was mainly conducted at Argonne National Laboratory, USA. At this stage, the key area of research was thermal conductivity under macroscopically static conditions. Few researchers have observed in their investigations that addition of nanoparticles in conventional fluids remarkably enhanced their thermal conductivity [27– 39,139–141] in comparison to the base fluids. Saidur et al. [40] observed that the thermal conductivity of nanofluids increased with the increase of particle volumetric concentration in base fluid. The mixing of nanoparticles with base fluid may alter the thermo-physical properties of fluids as the nanoparticles possess higher thermal conductivity than base fluids [25,41]. However, various experiments have shown that the increase of thermal conductivity might be offset by an increase of viscosity and noticed a little penalty in pressure drop [42–45]. Tiwari et al. [46,47] observed that an increase of nanoparticle volume concentration increased the viscosity and density of fluid, which, in turn, caused a pressure drop, and hence, increased the pumping power. Increment of shear viscosity of nanofluids as a function of nanoparticle concentration can also be seen in Fig. 1. Vajjha and Das [48] observed that increase of nanoparticle loading in the base fluid increased viscosity and density significantly. They observed an increment of 91% in viscosity and  13.9% in density at 6 vol% Al2O3/EGþ water (60:40) nanofluid. They also found that at a given temperature, all three nanofluids at 2 vol% (CuO, Al2O3 and SiO2) required less pumping power than the base fluid. However, CuO

nanofluid required more pumping power than the base fluid at a higher volumetric concentration ( 43 vol%). This can be well explained by Fig. 2. Thus, an increase of viscosity may incur a penalty in pressure drop and rise in pumping power. Hence, viscosity of nanofluids can play a vital role in selection of the nanofluid for a particular application. The pressure drop in any fluid is also affected by Reynolds number. A few researchers [49–55] have observed that an increase of Reynolds number of any fluid flow increased its pressure drop. Moreover, as shown in Fig. 3, there is a small increase in pressure drop with the increasing particle volume concentrations. In the present paper, however, the review is restricted to summarizing the effects of nanoparticle type, shape, shear rate range and volumetric concentration on rheological flow behaviour. Furthermore, the rheological behaviour of a nanofluid can also give an idea of viscosity variation with shear rate. The detailed rheological analysis of nanofluids [62–135] is sufficient to explain that they can exhibit either or both Newtonian and non-Newtonian behaviours. This behaviour depends on various factors such as nanoparticle shape [28,56–57], size [64], nanoparticle concentration [58–60], nanoparticle structure [61], surfactants [70,75,77– 78,80,83,104–106,112,116,125,128], shear rate range [70,96,114] and even magnetic field [125–135]. Furthermore, Wang et al. [137] reviewed literature available on rheology of nanofluids and found Brownian motion and nanoparticle aggregation to be the major mechanisms for rheological properties of nanofluids. The rheological behaviour of nanofluid, being an important factor in its application, might be helpful in understanding the viscosity profile

Fig. 1. Shear viscosity of nanofluids as a function of nanoparticle concentration [57].

Fig. 3. Variation of pressure drop versus Reynolds number for different particle volumetric concentrations [53].

Fig. 2. Pumping power versus particle volume concentration [48].

Table 1 Summary of rheological behaviour of different nanofluids. Nanoparticle/base fluid

Volumetric solid concentrations (ϕ)

Particle size (nm)

Shear rate range (s  1)

Findings

References

SiO2, TiO2/deionized water

0.468

0.16–1.73 mm

0–500

Richmond et al. [62]

TiO2/pure water

0.05–0.12

7–20

10–1000

TiO2/distilled water

0.24, 0.6 and 1.18

Primary size 20, 95 0.1–1000

TiO2/EG

0.1, 0.21, 0.42, 0.86 and 1.8

25

0–200

TiO2/EG

0.5, 2 and 8.0 wt%

70-100

0.5–104

TiO2/distilled water

0.12, 0.24, 0.6

10

1–104

TiO2/water TiO2/EG TNT/water TNT/EG TiO2/deionized water

0–2

Dia ¼10 Length ¼100

0.03–3000

SiO2 alone exhibited Newtonian behaviour while all SiO2/TiO2 mixed suspensions showed Bingham plastic behaviour. Due to the addition of a small amount of TiO2, the plastic viscosity increased remarkably compared to pure SiO2 suspension. A shear thinning behaviour was observed in all suspensions over all shear rate values. As solid concentration exceeded 0.1%, the flow curves of suspensions became apparently thixotropic. All the suspensions showed strong shear thinning behaviour till the shear rate reached 100 s  1 and after this it showed Newtonian behaviour. Also, shear viscosity increased with increasing nanoparticle loading and size. All suspensions behaved as Newtonian fluid. The relative viscosity depended on nanoparticle concentration in a non-linear manner but was independent of temperature. Both pure EG and EG-based nanofluids showed Newtonian behaviour. Also, viscosity increased with temperature and nanoparticle concentration. Suspensions showed shear thinning behaviour. The intensity of shear thinning behaviour of suspension increased with an increase in particle concentration. The viscosity decreased with an increase of temperature. TiO2/EG showed Newtonian behaviour while rest of the three nanofluids exhibited non-Newtonian behaviour.

0.2–3

21

n

TiO2/water

0.013, 0.020, 0.029, 0.050

5–6/80–90

0–100

TiO2/water Al2O3 TiO2 CuO/aqueous solution (0.5 wt%) of CMC

0.05–0.65 0.1, 0.2, 0.5, 1.0, 1.5, 3.0, 4.0

20, 25, 40, 100 25 10 30–50

Anatose TiO2/EG Rutile TiO2/EG

1.51–8.83 1.36–8.08

357 17 477 18

0.1–1000

MWCNT/polycarbonate

0.5, 1, 2 and 5 wt%

10–15

n

MWCNT/poly α-olefin (PAO6) oil

0.12

n

100

MWCNT/vinyl ester-polyster

0.05, 0.1, 0.3 wt%

15

10  1–103

MWCNT/poly α-olefin (PAO6) oil

1 wt%

100

100

MWCNT-Al2O3/glycerol(10 wt%) and water

20, 25, 30, 35, 40, 45

Al2O3(27.5) CNT (10–30)

1–200

He et al. [64]

Chen et al. [65]

Chen et al. [66] Chen et al. [67]

Chen et al. [68]

Turgut et al. [69]

Alphonse et al. [70]

Penkavova et al. [71] Hojjat et al. [72]

Cabaleiro et al. [73]

Potschke et al. [74]

A.K. Sharma et al. / Renewable and Sustainable Energy Reviews 53 (2016) 779–791

n

350–1000

Suspension having lower volumetric concentration (0.2) showed almost Newtonian behaviour but for higher concentrations it exhibited non-Newtonian behaviour. In the shear rate range 1–100 s  1, the suspension showed Newtonian behaviour while for higher shear rate ( 4100 s  1), it showed shear thinning behaviour. Nanofluids showed Newtonian behaviour. Base fluid as well as all the suspensions showed non-Newtonian (shear thinning) behaviour. The relative apparent viscosity of TiO2 and Al2O3 nanofluids increased with an increase of nanoparticle concentration, while for CuO nanofluid, it was found to be almost independent of concentration. Both types of suspensions exhibited non-Newtonian (shear thinning) behaviour. Viscosity decreased with increasing volumetric concentration. At approx. 10 s  1 shear rate, the viscosity of both nanofluids was found to be independent of temperature. Composites having more than 2 wt% MWCNT showed Non-Newtonian behaviour at lower frequencies while 0.5 and 1% exhibited Newtonian behaviour. The suspensions with lowest (0.3%) and highest (8%) dispersant concentrations reported strong thinning behaviour while the suspension with 3 wt% dispersant showed Newtonian behaviour. This suspension with lower particle loading ( o 0.09 vol%) showed Newtonian behaviour, while for 0.09 vol% and 0.13 vol%, it showed slight shear thinning at low stress. Neat resin suspension showed almost Newtonian behaviour but MWCNT enriched base fluid showed shear thinning behaviour. At 25 °C, suspensions without dispersant behaved slightly like shear thinning, but, at 75 °C, suspension showed very strong shear thinning behaviour. Both Al2O3 and MWCNT-Al2O3 suspensions exhibited shear thinning behaviour. With an increase of nanoparticles, loading in suspension increased its viscosity.

Tseng and lin [63]

Yang et al. [75]

Seyhan et al. [76] Yang et al. [77]

Lu [78]

781

782

Table 1 (continued ) Nanoparticle/base fluid

Volumetric solid concentrations (ϕ)

Particle size (nm)

Shear rate range (s  1)

Findings

References

MWCNT/1-butyl-3-methylimidazolium hexafluorophosphate (Bmim PF6)

0.1 wt%

Dia 20–40 Length ¼5–15 mm

10  2–103

Wang et al. [79]

MWCNT/deionized water

0.24–1.43

20–30

0–200

MWCNT/EG

0.5–4% mass fraction

MWCNT/EG

0.5 wt%

10–30

0.1–100

MWCNT/deionized water

0.05, 0.24, 1.27

20–30

1–120

MWCNT/distilled water

600, 1400, 2200 ppm

n

0.01–100

SiO2/ethanol

1.1–7.0

35, 94, 190

0–5  104

Suspensions at low concentrations ( o ¼ 0.04 wt%) showed shear thinning behaviour at low shear rate but behaved as Newtonian fluid at high shear rate. The nanofluids containing higher concentration ( 40.06 wt%) exhibited shear thinning behaviour. Interestingly, the viscosity of nanofluids was found to be lower than that of the base fluid at much higher shear rate. Viscosity of nanofluids reduced with an increase of temperature. Suspension with low CNT concentration ( o 0.24 vol%) and 0.1–0.2 wt%, chitosan behaved as Newtonian fluid while with high CNT concentration and 0.1–0.2 wt%, chitosan exhibited shear thinning behaviour. Nanofluids exhibited Newtonian behaviour. Viscosity decreased with an increase in temperature. Viscosity of 4% MWCNT nanofluid at 55 °C was found to be much lower than that of pure EG at 25 °C. Suspension showed shear thinning behaviour. Suspension with sonication time of 40 min. exhibited the highest viscosity. Furthermore, the suspension with sonication time of 1355 min. showed a flat curve comparable to that of pure EG on stress–shear rate plot approaching Newtonian behaviour. Interestingly, the viscosity at a fixed shear rate first increased then decreased with an increase in sonication time. At a high volumetric concentration, nanofluid showed a clear shear thinning behaviour. Viscosity increased with rise of concentration and decreased with rise of temperature. Surfactant produced better stability of nanofluid. All the suspensions showed shear thinning flow behaviour. Surfactant increased the viscosity slightly as compared to distilled water and also mildly increased its friction factor. Suspensions showed Newtonian behaviour over a wide range of shear rates. Also viscosity increased with increase of nanoparticle concentration. Viscosity of nanofluids increased with an increase of nanoparticle concentration and decreased by the increase in temperature. Rheology of suspensions was investigated under very high shear rates. All the nanofluids showed Newtonian behaviour. All the clay-based fluids showed a strong shear thinning behaviour.

0.45, 1.85, 4 12 0.5, 1.5 30 0.4, 0.7, 1, 1.1, 1.3, 1.6, 2.6, 3.1 10–100

n

10–1000

Hybrid ICH and ASCH/aqueous 5 wt% bentonite 0.5 wt% fluid (5B) Silica/distilled water 0.002–0.132

2

1–200

12

0.1–1000

SiO2/paraffinic mineral oil

1.0, 2.0

20

1–1000

Al2O3/pure water

0.01–0.16

37

1–1000

Al2O3/double distilled water

0.01–0.15

0.2 mm

1–1000

Alumina/PG Al2O3/water Al2O3/EG CuO/EG

0.5, 2.0 and 3.0 0.5, 1, 2, 4, 6

27, 40, 50 50

0–100 1–1000

Suspensions containing low concentration ( o 0.069 vol%) behaved as Newtonian fluids while nanofluids with higher particle concentration became shear thinning in nature. Both base fluid and suspensions showed Newtonian behaviour at  30 °C. However, shear thinning behaviour in both was observed at elevated temperature (  100 °C) and pressure. Viscosity of both the base fluid and nanofluids increased with an increase of pressure. The suspension generally showed a transition from shear thinning to shear thickening as the shear rate exceeded a certain critical level of approx.100 s  1. Also, this critical value of shear rate increased with a rise of nanoparticle concentration. However, pH 11 suspensions showed shear thinning behaviour over the entire range of shear rate and no transition in flow behaviour could be seen. All suspensions containing Al2O3 micro-sized particles (  0.2 mm) showed shear thinning flow behaviour at low shear rate values followed by shear thickening behaviour as shear rate surpassed a critical value. For all suspensions, this critical value increased with an increase of solid concentration (ϕ). All the suspensions were found to be Newtonian in nature. All nanofluids exhibited Newtonian behaviour.

Meng et al. [81]

Ruan and Jacobi [82]

Wang et al. [83]

Ko et al. [84]

Chevalier et al. [85] Tavman et al. [86] Chevalier et al.[87] Jung et al. [88] Mondragon et al.[89]

Anoop et al.[90]

Tseng and Wu [91]

Tseng and Wu [92]

Prasher et al. [93] Anoop et al. [94]

A.K. Sharma et al. / Renewable and Sustainable Energy Reviews 53 (2016) 779–791

SiO2/deionized water Al2O3/deionized water SiO2/ethanol

10–120

Phuoc et al. [80]

0.005–0.066

40–50

123

Al2O3/water CNT/water

1 wt%

30 nm 9 mm

10  1–5000

CuO/deionized water

n

30, 75 and 150

0–20

CuO/EG

10  5  10  1 (dilute limit¼ 0.002)

10–30

10  2–103

CuO/EG and water mixture (60:40 by wt.)

1, 2, 3, 4, 5 and 6.12

29

0–8

CuO/PG þ water (60:40)

0.025, 0.1, 0.4, 0.8 and 1.2

o 50

500–700

CuO/water

0–0.018

23–37 117 3

CuO/oil (SN-500)

0.2, 0.5, 1.0, 2.0 wt%

50

1–17

CuO/0.4 wt% Xanthan gum aqueous solution ZnO/0.4 wt% Xanthan gum aqueous solution BaTiO3/distilled water

0.1, 0.3, 0.5 wt%

10–1200

0.1–0.55

o 50 o 50 0.8 mm

BaTiO3/ethanol–isopropanol

0.3–0.6

0.58 mm

1–1000

Nickel/terpineol

0.03–0.1

0.3 mm

1–1000

Nickel/α-terpineol

0.01–0.28

90

1–1000

Aluminium/HTPB, PPG and PSi

2.1, 6.25 and 10

120

10  3–103

Aluminium(ALEX)/paraffin oil Aluminium/HTPB

2–45 2–47

Silver/DEG

0.11–4.38

40

1–200

Silver/BCA and CA in weight ratio 5:1 Graphite/oil

1.0–16 0.17–1.36

30–50 10–30

1–4000 0.1–1000

1–1000

10  3–104

Gallego et al. [95]

Aladag et al. [96]

Chang et al. [97]

Kwak and Kim [98]

Namburu et al. [99]

Naik et al. [100] Pastoriza et al. [101]

Saeedinia et al. [102]

William et al. [103] Tseng and Li [104]

Tseng and Lin [105]

Tseng and Chen [106]

Tseng and Chen [107]

Mary et al. [108]

Teipel and Barth [109]

Tamjid and Guenther [110] Chen et al. [111] Wang et al. [112] 783

Suspension exhibited Newtonian behaviour at tested shear rate (123 s  1). Viscosity increased with concentration of nanoparticles and decreased with temperature rise. CNT nanofluid behaved almost as Newtonian fluid for high shear rates ( 4100 s  1) and as non-Newtonian fluid for low shear rates. Al2O3 suspension exhibited non-Newtonian shear thickening behaviour. Also, both the nanofluids showed thixotropic nature. The viscosity decreased with the temperature rise. Suspensions having small particles (30 and 75 nm) exhibited pseudoplastic nature while with large sized particles (150 nm) showed pseudoplastic behaviour with a yield stress. Also, for very small shear rate values ( o 5 s  1), a rapid drop in viscosity was observed and no apparent change in viscosity could be seen when shear rate was higher than 5 s  1. Moreover, suspensions containing smaller sized particles had higher viscosity. All the suspensions exhibited very strong shear thinning character. For very higher shear rate values, all suspensions had almost the same viscosity as that of the base fluid. All suspensions showed Newtonian behaviour. The viscosity of suspensions increased with an increase of nanoparticle loading and decreased exponentially with temperature. Nanofluids exhibited Newtonian behaviour. Viscosity decreased exponentially with the increase of temperature. Nanofluids exhibited Newtonian behaviour. Viscosity increased with an increase of nanoparticle concentration and decreased with rise of temperature. All suspensions exhibited Newtonian behaviour at different temperatures. Viscosity decreased with an increase in temperature and increased with nanoparticle concentration. All suspensions showed shear thinning behaviour. Viscosity of nanofluids decreased with an increase of temperature. Suspension without NH4PA appeared to be shear thinning. As shear rate exceeded  400 s  1, it followed Bingham plastic nature. But adding NH4PA (2 wt%), the suspension appeared to be close to Newtonian behaviour at a low shear rate (  100 s  1), while for higher values of shear rate, the stress– shear rate curve deviated from linearity and revealed dilatant flow behaviour. All suspensions showed shear thinning behaviour at a low shear rate (  20– 60 s  1) and moved towards Bingham plastic nature as shear rate increased further and followed by shear thickening behaviour at high shear rate values. All suspensions containing nickel powder (average particle size  0.3 mm) appeared to have shear thinning flow behaviour over the entire range of shear rate. The Ni–terpineol suspensions generally exhibited shear thinning behaviour. But for lower solid concentrations ( o 0.05 vol%), the suspensions followed shear thickening flow behaviour. The rheology of polyethylene coated and uncoated aluminium nanoparticles was investigated in this work. The uncoated HTPB suspension displayed Newtonian behaviour while HTPB coated suspensions showed shear thinning behaviour for 6.25 and 10 vol%. Both the PPG and PSi suspensions reported shear thinning behaviour even for uncoated particles. ALEX-paraffin oil suspension showed shear thinning behaviour while ALEXHTPB suspension exhibited almost Newtonian behaviour for a wide range of nanoparticle concentration. The suspensions exhibited non-Newtonian (pseudoplastic) flow behaviour. Viscosity increased with an increase of particle concentration. All suspensions showed shear thinning behaviour. Suspensions exhibited shear thinning flow behaviour. Addition of surfactant and graphite nanoparticles increased the viscosity of nanofluids. Viscosity also decreased with an increase of temperature.

A.K. Sharma et al. / Renewable and Sustainable Energy Reviews 53 (2016) 779–791

Al2O3/EG

784

Table 1 (continued ) Nanoparticle/base fluid

Volumetric solid concentrations (ϕ)

Particle size (nm)

Shear rate range (s  1)

Findings

References

Graphite/deionized water

1–4

3–4

1–100

Duan et al. [113]

Graphene/glycerol

0.0025–0.02

15–50

1–180

GNP/distilled water

0.025, 0.05, 0.075, 1.0 wt%

Thickness-2 nm Dia-2 mm

1–200

ITO/deionized water

0.2–0.3

60

10–500

TNT/EG

0.1, 0.21, 0.42, 0.86, 1.80

10

10  1–103

ZnO/EG

0.01–0.05

10–20

0–100

TNT/EG

0.5, 1.0, 2.0, 4.0, 8.0

Dia ¼10 Length ¼100

10  1–103

CaCO3/distilled water MgO/EG

0.12, 0.48, 1.40, 2.05, 4.11 0.5–5

20–50 20

5–100 10–150

Gold/water

0.01

10, 20, 50

200–2000

Carbon black powder (N115)/EG

2.2, 5.6, 7.8

20

6–120

Yttrium oxide(Y2O3)/EG Magnesium–aluminium spinel(MgAl2O4)/EG

1, 5, 10, 15, 20 wt%

317 1 407 1

0.01–2000

Suspension behaved as shear thinning fluid. The viscosity increased with the increased loading of nanoparticles. Enhancement of viscosity of suspensions, held for 3 days, was much higher than the freshly prepared nanofluids for the same volume of concentration. At low shear rates, the suspensions showed shear thinning behaviour for all temperatures. But for high shear rates, the nanofluids behaved as Newtonian fluids. Shear thinning behaviour became more prominent with increasing nanoparticle concentration. All the suspensions exhibited shear thinning behaviour. The shear thinning behaviour was found to be more pronounced at higher concentrations. Viscosity of all nanofluids decreased with an increase of temperature. All the suspensions showed Newtonian flow behaviour over a range of shear rates. Besides this, suspensions behaved as Bingham fluid for lower shear rates, while for very high shear rates, it showed shear thickening behaviour. TNT–EG nanofluids exhibited shear thinning behaviour. The shear viscosity increased with the TNT concentration. Nanofluid with lower particle concentration (o 0.02) exhibited Newtonian behaviour while suspension having higher volumetric concentrations ( 40.03) nanofluids possessed shear thinning behaviour. All suspensions behaved as slightly shear thinning fluid for low particle concentration (r 2.0%), while for higher TNT concentration, they exhibited very strong shear thinning behaviour. Nanofluids with higher temperatures exhibited stronger shear thinning behaviour as compared to suspensions at lower temperatures. The viscosity showed an increasing trend with an increase of temperature for lower shear rates ( o 10 s  1 ), while for higher shear rates ( 4 10 s  1), a reverse trend was noticed. All suspensions showed Newtonian behaviour. Suspensions showed Newtonian behaviour. Viscosity of suspensions increased with an increase of nanoparticle concentration and decreased with a rise in temperature. The nanofluids exhibited Newtonian behaviour. Nanofluids with largersized (50 nm) nanoparticles possessed higher viscosity as compared to the suspensions having smaller sized (10 and 20 nm) nanoparticles. Also, viscosity decreased with the rise of temperature. Suspensions showed shear thinning behaviour and the extent of this behaviour increased with an increase of carbon black inclusion into EG. Furthermore, shear viscosity decreased with an increase of temperature at the same shear rate. Y2O3 nanofluid showed non-Newtonian behaviour. MgAl2O4 suspension showed Newtonian behaviour for low particle concentration while it exhibited shear thinning behaviour for higher (15 and 20 wt%) particle concentration. Temperature did not have significant effect on the viscosity of MgAl2O4 suspension at high shear rate.

not mentioned.

Mehrali et al. [115]

Tseng and Tzeng [116]

Chen et al. [117] Yu et al. [118]

Chen et al. [119]

Tao et al. [120] Xie et al. [121]

Abdelhalim et al. [122]

Meng et al. [123]

Cholewa et al. [124]

A.K. Sharma et al. / Renewable and Sustainable Energy Reviews 53 (2016) 779–791

n

Moghaddam et al. [114]

Table 2 Summary of magneto-rheological behaviour of different nanofluids. Volumetric solid concentrations (ϕ) Particle size (nm)

Shear rate range (s  1)

Behaviour/findings

References

Fe3O4/deionized water

Low 0.7, 1.6, 2.0, 0.6, 0.5, High 37.3, 33.1, 30.8, 28 wt%

1.5  107–4.5  107

Hong et al. [125]

Fe3O4/deionized water

10, 15, 25, 35 wt%

 10

1–100

Fe3O4–TiO2/silicone oil (TiO2 coated Fe3O4) Fe2O3/deionized water

30 wt%

10

0–100

0.01, 0.02, 0.03, 0.04

20–40

13.2–264

Fe2O3/EG Fe2O3/glycerol

6.6 0.25–0.8

297 18 26

1–1000 0.01–264

Magnetite/transformer oil

0.8–21

6–7

1–1000

Fe–Ni/paraffin oil

2–12 wt% (optimum 10 wt%)

o 15

1–100

Fe3O4/polyethylene glycol (PEG)

0.48, 1.0, 3.05, 3.6

30

0.01–1000

All suspensions followed shear thinning behaviour. Among low concentration suspensions, i.e., sample 1–5, the sample with 0.5 wt% possessed the highest viscosity while among higher concentration samples (6–9), the suspension with 37.3 wt% exhibited the highest viscosity. Low concentration suspensions (10 and 15 wt%) showed Newtonian behaviour. The suspension containing 25 wt% nanoparticles exhibited shear thickening behaviour while 35 wt% suspension showed shear thinning behaviour. Suspension showed slight departure from Newtonian behaviour without magnetic field. Under magnetic field, the suspension exhibited Bingham plastic behaviour. Suspension having 0.2 wt% PEO behaved as Newtonian fluid when ϕ was less than 0.02 and exhibited shear thinning behaviour for higher nanoparticle concentration. The same behaviour was noticed with 0.2 wt% PEO. However, the latter suspension switched to shear thinning behaviour at ϕ as low as 0.02. Suspensions showed shear thinning behaviour and also thixotropy. Nanofluids exhibited shear thinning behaviour. Viscosity increased with concentration of nanoparticles and decreased with temperature rise. Except for the most concentrated suspension (20.8%), all the suspensions showed Newtonian behaviour. Viscosity increased with particle loading. Without magnetic field, the nanofluid with 10 wt% loading possessed pseudoplastic nature. As magnetic field increased, the fluid behaved as Bingham plastic fluid. All suspensions showed shear thinning behaviour.

γ-Fe2O3/iso-butanol γ-Fe2O3/methyl-ethyl-ketone (MEK)

0.05–0.6

o 10

1–1000

Fe3O4/transfer oil(TR30)

1.8, 2.0, 3.6, 6.4

5.94– 6.8

*

*

Hong et al. [126]

Wei et al. [127] Phuoc and Massoudi et al. [128]

Gallego et al. [129] Abareshi et al. [130] Resiga et al. [131] Katiyar et al. [132] Moattar and Cagincara [133] Vekas et al. [134]

Iso-butanol-based nanofluid showed Newtonian behaviour while MEK-based nanofluid exhibited shear thinning behaviour. The magnetic field did not affect the rheological flow behaviour of iso-butanol-based nanofluid but an increase in magnetic induction to the MEK-based nanofluid changed its flow behaviour from Newtonian to strongly non-Newtonian. At low magnetic field value, a slight increment and at 0.04 T a strong increment in Vekas et al. [135] viscosity was observed. Viscosity increased further, but, at about 0.07 T, the viscosity decreased. Further on, the viscosity decreased even with the increase in magnetic field.

A.K. Sharma et al. / Renewable and Sustainable Energy Reviews 53 (2016) 779–791

Nanoparticle/base fluid

not mentioned.

785

786

A.K. Sharma et al. / Renewable and Sustainable Energy Reviews 53 (2016) 779–791

of any nanofluid, whether varying or constant with shear rate. Also, the non-Newtonian fluid behaviour and shear ratedependent viscosity of nanofluid require careful consideration in its processing and application. A significant amount of research work has already been compiled and reviewed on heat transfer and viscosity of nanofluids. However, very few studies on rheological behaviour of nanofluids have been published. In this paper, the authors attempt to review important research works available on rheological behaviour of nanofluids at different shear rate ranges and particle volume concentrations. A brief discussion on the effect of surfactants and magnetic field on rheological behaviour of nanofluids has also been included here.

2. Rheological behaviour of nanofluids The rheological flow behaviour of any fluid is explained in terms of the relationship between shear stress (τ) and shear rate (γ). The shear stress is defined as the tangential force applied per unit area and the shear rate is stated as the change of shear strain per unit time. The ratio of shear stress to shear rate is known as viscosity (η), which can also be defined as a measure of resistance offered by the adjacent layers to one another during the flow of liquid suspension. The fluid behaviour can be categorised as Newtonian and non-Newtonian (pseudoplastic, Bingham plastic, Bingham and Dilatant). For Newtonian behaviour, the viscosity remains constant with shear rate and the stress exhibits linear relation with shear rate while for non-Newtonian behaviour, the viscosity may vary with shear rate and correlation between stress and shear rate follows Bingham plastic behaviour. 2.1. Newtonian and non-Newtonian behaviour of nanofluids Rheological behaviour of nanofluids affects pressure drop of nanofluids. Additionally it gives an idea of nanoparticle structuring, which can be helpful in predicting the thermal conductivity of nanofluids. The rheological behaviour can be measured by rheometers [64–68,70,72]. Some researchers [62–63,69,71] have used viscometers to measure the viscosity. Nowadays viscometers are considered inadequate as they are not capable to read the feature of shear dependence, especially for low viscosity liquid-based nanofluids containing non-spherical particles. Richmond et al. [62] have found that mixing of TiO2 in SiO2/water nanofluid changes its flow behaviour from Newtonian to non-Newtonian. One can conclude that except for the behaviour as observed by Penkavova et al. [71], the TiO2/water nanofluid shows shear thinning behaviour [63,64,67–68]. The TiO2/EG nanofluid exhibits Newtonian behaviour even for high shear rate. MWCNT nanofluid showed Newtonian and non-Newtonian behaviour both, depending upon the type of base fluid. A clear shear thinning behaviour was reported by MWCNT mixed in water, oil, resin and EG [74– 80,82–84] except in the case of MWCNT/EG [81]. The glycerol based and silicone oil based fluids behave Newtonian manner in all studied MWCNT volume fractions and temperatures [138]. Nanofluids containing MWCNT with high volumetric concentration show non-Newtonian behaviour, while with lower concentration, nanofluids exhibit Newtonian behaviour [74,75]. All the suspensions containing SiO2 nanoparticles show Newtonian behaviour [85–90]. Al2O3/water nanofluid show non-Newtonian behaviour [91,92] while Al2O3/EG and Al2O3/PG behave as Newtonian fluid [93–95]. Water-based nanofluid containing microsized Al2O3 particle exhibits shear thinning behaviour. The rheological behaviour of various nanofluids enriched with nanoparticles, such as, CuO, BaTiO3, Ni, Al, Ag, graphite, grapheme,

CaCO3, TNT, Gold, Carbon black powder and Yttrium oxide has been systematically summarized and analysed in Table 1. 2.2. Rheological behaviour of ferrofluids Ferrofluids are suspensions of ferromagnetic and ferromagnetic nanoparticles (Fe3O4, Fe2O3, Fe, γ-Fe2O3 etc.) in polar and nonpolar carrier liquids. The ferrofluids are better known for their apparent viscosity, capable of experiencing a rapid reversal upon application of external magnetic field. The rheological behaviour of different ferrofluids has been summarized in Table 2. Hong et al. [125,126] observed that Fe3O4/water nanofluid showed Newtonian behaviour for low particle concentration but exhibited shear thickening behaviour followed by shear thinning behaviour for higher concentration. Fe2O3 mixed in EG [129] and glycerol [130] showed shear thinning behaviour while magnetite in transformer oil exhibited Newtonian behaviour. Under the influence of external magnetic field, Fe3O4–TiO2/silicone oil [127] and Fe–Ni/paraffin oil nanofluids [132] showed a departure from the Newtonian to Bingham plastic behaviour. Vekas et al. [135] observed an increment in the viscosity with the increase of magnetic field but upto a certain value. After that, the viscosity decreased further even with an increase of magnetic field. 2.3. Effect of surfactants on rheological behaviour of nanofluids Surfactants are often used in the preparation of stable nanofluids. Stabilization of the nanofluids is generally considered vital in achieving uniform particle packing structure throughout the suspension. The influence of mixing surfactant on the rheological behaviour of nanofluid is summarized and analysed in Table 3. Phuoc et al. [80] and Wang et al. [83] observed that addition of surfactant in MWCNT/water nanofluid changed its flow behaviour from Newtonian to non-Newtonian. The mixing of NH4PA as surfactant in BaTiO3/distilled water nanofluid [104] changed its flow behaviour from Newtonian to dilatant for higher shear rate values. The addition of surfactant changed the rheological behaviour of BaTiO3/ethanol isopropanol from pseudoplastic to dilatant [105] even though it did not affect the flow behaviour of Ni/terpineol nanofluid [106].

3. Conclusions This review work has focussed on the rheological behaviour of nanofluids and ferrofluids under wide range of shear rate and nanoparticle volumetric concentration. It has studied important literature available on rheological behaviour of nanofluids. It has also attempted a brief analysis of the influence of magnetic field and surfactant on rheological behaviour of nanofluid. The effect of different base fluids, shear rate range, nanoparticle concentration and nanoparticle shape has also been compiled and analysed. The following conclusions are drawn from this study:

 Most of the nanofluids containing low nanoparticle concentra-

 

tion behave as Newtonian fluid and nanofluid with high concentration exhibits non-Newtonian behaviour as shown in Table 4. Nanofluids show Newtonian behaviour at low shear rate and exhibit non-Newtonian behaviour at high shear rates as shown in Table 4. Spherical nanoparticles are more likely to exhibit Newtonian behaviour while nanoparticles having tubular and tetragonal shapes show non-Newtonian behaviour as shown in Table 4.

A.K. Sharma et al. / Renewable and Sustainable Energy Reviews 53 (2016) 779–791

787

Table 3 Summary of effect of dispersant on rheological behaviour of nanofluids. Nanoparticle/base fluid

Dispersant/surfactant

Behaviour/findings

References

TiO2/water

Poly ethylene glycol (PEG) 2000

Alphonse et al. [70]

MWCNT/poly α-olefin (PAO6) oil

Polyisobutene succinimide (PIBSI) (0.3– 8 wt%)

MWCNT/poly α-olefin (PAO6) oil

PIBSI 1000 and PIBSI 500 3 wt%

MWCNT-Al2O3/glycerol (10 wt%) and water

Poly-acrylic acid (PAA)

MWCNT/deionized water

0.2 wt% Chitosan

MWCNT/deionized water

Sodium dodecyl benzene sulphonate (SDBS) and TritonX-100

BaTiO3/distilled water

Ammonium polyacrylate (NH4PA)

BaTiO3/ethanol– isopropanol

Polymeric dispersant (anionic and cationic) KD1,2,6,7 and PS-2

Nickel/terpineol

Polymeric dispersant (anionic and cationic) KD1,2,4,5,6,7 and PS-2

The addition of PEG 2000 first reduced the viscosity to a minimum value (about 50–60% of the viscosity of nanofluid without PEG). On further addition of PEG 2000, the viscosity increased steadily. The suspensions with the lowest (0.3%) and the highest (8%) dispersant concentrations reported strongly thinning behaviour while the suspension with 3 wt% dispersant followed Newtonian behaviour. At 25 °C, the suspensions without dispersant displayed slightly shear thinning behaviour but at 75 °C dispersion showed very strong shear thinning behaviour. Suspension with PIBSI 1000 showed mild shear thinning behaviour, while by adding PIBSI 500, the suspension displayed very strong thinning behaviour. On adding PAA in suspension, it was absorbed on particle surface. The substantial colloidal interactions were observed when the nanoparticle loading was 4 35 vol% and CNT content was 41.3 vol%. Suspension with low CNT concentration ( o 0.24 vol%) and 0.1– 0.2 wt% chitosan behaved as Newtonian fluid while with high CNT concentration and 0.1–0.2 wt% chitosan exhibited shear thinning behaviour. Adding low wt% of chitosan (0.1, 0.2 wt%) in water increased its viscosity significantly while adding 0.5 wt% chitosan in water decreased its viscosity and changed the flow behaviour of suspension toward non-Newtonian behaviour. Viscosity increased with the rise of concentration and decreased with the rise of temperature. Surfactant produced better stability of nanofluid. Adding NH4PA (2 wt%), the suspension appeared to be near Newtonian behaviour at a low shear rate (  100 s  1), while for higher values of shear rate, the stress–shear rate curve deviated from linearity and revealed dilatant flow behaviour. Addition of dispersant also changed the flow behaviour of suspension from pseudoplastic to dilatant as shear rate surpassed  800 s  1. The viscosity of suspension reduced to the lowest level by the addition of a polymeric dispersant KD-6 (3 wt%). The addition of dispersant did not affect the flow behaviour. Also, addition of polymeric dispersant (KD-6 at 2 wt%) to suspension reduced the viscosity to minimum, almost 60% of the suspension having no dispersant. All suspensions showed a shear thinning behaviour. Polymeric 9250 surfactant alleviated the agglomeration of silver nanoparticles in suspension. Addition of surfactant and graphite nanoparticles increased the viscosity of nanofluids, Viscosity decreased with an increase of temperature. Addition of 0.5–2 wt% NH4PA in the suspension reduced its viscosity approximately by 99% as compared to original suspension. The suspension behaved as Bingham fluid at low shear rates and showed changing nature toward shear thickening flow behaviour when shear rate exceeded a critical level. Viscosity of suspension decreased with increasing PEG dosage. The viscosity of suspension was the lowest for 2.9% oleate sodium and 2.9% PEG (Maximum solid content of 2.0 wt%). The viscosity reached the maximum for suspension containing 2.8% oleate sodium and 4.7% PEG (least solid content of 0.5 wt%). The surfactants could not only hold the sedimentation and aggregation of nanoparticles but also introduced thixotropic effect. Suspension having 0.2 wt% PEO behaved as Newtonian fluid when ϕ was less than 0.02 and exhibited shear thinning behaviour for higher nanoparticle concentration. The same behaviour was noticed with 0.2 wt% PEO. However, the latter suspension switched to shear thinning behaviour at ϕ as low as 0.02.

Silver/BCA and CA in weight Polymeric 910, 9250 and KD-6 ratio 5:1 Graphite/oil

CH-5

ITO/deionized water

Ammonium polyacrylate (NH4PA)

Fe3O4/deionized water

Oleate sodium, PEG-4000

Fe2O3/deionized water

Polyvinylpyrrolidone (PVP) or Polyethylene oxide (PEO)

 TiO2 mixed in viscous liquid like EG shows Newtonian beha  

viour, while with low viscous liquid like water, it exhibits nonNewtonian behaviour. MWCNT nanofluid mostly exhibits shear thinning behaviour for low shear rates. However, sometimes it shows Newtonian behaviour at high shear rate range. SiO2 nanofluids, irrespective of base fluid, display Newtonian behaviour over a wide range of shear rates. Al2O3 nanofluids show a transition from shear thinning behaviour to shear thickening as shear rate exceeds certain critical

 



Yang et al. [75]

Yang et al. [77]

Lu [78]

Phuoc et al. [80]

Wang et al. [83]

Tseng and Li [104]

Tseng and Lin [105]

Tseng and Chen [106]

Chen et al. [111]

Wang et al. [112]

Tseng and Tzeng [116]

Hong et al. [125]

Phuoc and Massoudi et al. [128]

level. This critical value increases with an increase in nanoparticle concentration. CuO nanofluid exhibits almost Newtonian behaviour. However, with xanthan gum, it shows shear thinning behaviour. Nanofluids with highly viscous base fluid, such as, EG and PG, are more likely to possess Newtonian behaviour than those made of low viscous fluid like water. The conclusion is consistent with the results observed in the study by Chen et al. [57]. Addition of surfactant in nanofluid increases its viscosity and may also change its flow behaviour to dilatant.

788

A.K. Sharma et al. / Renewable and Sustainable Energy Reviews 53 (2016) 779–791

Table 4 Summary of nanoparticle type, shape, size and rheological behaviour. Nanoparticle/base fluid

Particle size (nm)

Nanoparticle shape

Rheological behaviour

References

SiO2, TiO2/deionized water

0.16–1.73 mm

Prismatic irregular shape

Richmond et al. [62]

TiO2/distilled water

20 95 25 70–100 10 Dia ¼ 10 Length ¼ 100

Spherical

SiO2 Newtonian SiO2/TiO2 Bingham plastic Shear thinning

TiO2/EG Titania/EG Titanate/distilled water TiO2/water TiO2/EG TNT/water TNT/EG TiO2/deionized water

Spherical Spherical Tube Spherical and tube both

He et al. [64]

21

Spherical

TiO2/water

5–6/80–90

Spherical

TiO2/water Anatose TiO2/EG Rutile TiO2/EG MWCNT/polycarbonate

20, 25, 40, 100 357 17 477 18 10–15

Spherical Tetragonal shape

MWCNT/poly α-olefin (PAO6) oil MWCNT/vinyl ester-polyster MWCNT/poly α-olefin (PAO6) oil MWCNT-Al2O3/glycerol(10 wt%) and water

* 15 100 Al2O3(27.5) CNT (10–30) Dia 20–40 Length ¼ 5–15 mm

Tube Tube Tube Tube

Newtonian Newtonian Shear thinning Newtonian Non-Newtonian Non-Newtonian Non-Newtonian Low conc. Newtonian while high conc. Non-Newtonian Newtonian for low shear rate and shear thinning for high shear rate Newtonian Non-Newtonian Non-Newtonian Newtonian for low conc. and NonNewtonian for nanoparticle high conc. Shear thinning Shear thinning Shear thinning Shear thinning

Tube

Shear thinning

Wang et al. [79]

Tube Tube Tube

Meng et al. [81] Ruan and Jacobi [82] Wang et al. [83]

Nano tube

Chen Chen Chen Chen

et et et et

al. al. al. al.

[65] [66] [67] [68]

Turgut et al. [69] Alphonse et al. [70] Penkavova et al. [71] Cabaleiro eet al. [73] Potschke et al. [74] Yang et al. [75] Seyhan et al. [76] Yang et al. [77] Lu [78]

MWCNT/1-butyl-3-methylimidazolium hexafluorophosphate (Bmim PF6) MWCNT/EG MWCNT/EG MWCNT/deionized water

10–30 20–30

MWCNT/distilled water SiO2/ethanol SiO2/ethanol Silica/distilled water

35, 94, 190 10–100 12

Tube Spherical Spherical Spherical

20 37 0.2 mm 27, 40, 50 50

Spherical spherical Spherical Spherical Spherical

Newtonian Shear thinning At high conc. Shear thinning but at low conc. Newtonian Shear thinning Newtonian Newtonian Low conc. Newtonian while high conc. Shear thinning Newtonian Shear thinning Non-Newtonian Newtonian Newtonian

Spherical Spherical Tube Spherical Rod like Spherical Spherical Spherical

Newtonian Non-Newtonian for low shear rates and Newtonian for high shear rates Pseudoplastic Shear thinning Newtonian Newtonian Newtonian

CuO/oil (SN-500) BaTiO3/distilled water BaTiO3/ethanol–isopropanol Nickel/terpineol Nickel/α-terpineol Aluminium/HTPB, PPG and PSi Silver/DEG

40–50 30 nm 9 mm 30, 75 and 150 10–30 29 o50 23–37 11 73 50 0.8 mm 0.58 mm 0.3 mm 90 120 40

Spherical Spherical Spherical Spherical Spherical Spherical Spherical

Newtonian Non-Newtonian Shear thinning Shear thinning Shear thinning Shear thinning Pseudoplastic

Silver/BCA and CA in weight ratio 5:1 Graphite/oil

30–50 10–30

Shear thinning Shear thinning

Graphite/deionized water

3–4

Shear thinning

Duan et al. [113]

Graphene/glycerol

15–50

Spherical Not spherical but complex crystalline shape Not Spherical but complex shape Platelets

Saeedinia et al. [102] Tseng and Li [104] Tseng and Lin [105] Tseng and Chen [106] Tseng and Chen [107] Mary et al. [108] Tamjid and Guenther [110] Chen et al. [111] Wang et al. [112]

GNP/distilled water

Platelets

Moghaddam et al. [114] Mehrali et al. [115]

ITO/deionized water

Thickness-2 nm Dia-2 mm 60

Non-Newtonian for high shear rate and Newtonian for low shear rates Shear thinning

Tseng and Tzeng [116]

(TNT)/EG ZnO/EG

10 10–20

Rod like Spherical

TNT/EG

Dia ¼ 10

Tube

Newtonian but Bingham plastic for very high shear rates Shear thinning Low conc. Newtonian while high conc. Shear thinning Shear thinning

SiO2/paraffinic mineral oil Al2O3/pure water Al2O3/double distilled water Alumina/PG Al2O3/water Al2O3/EG CuO/EG Al2O3/EG Al2O3/water CNT/water CuO/deionized water CuO/EG CuO/EG and water mixture (60:40 by wt.) CuO/PG and water (60:40) CuO/water

*

Spherical

Ko et al. [84] Chevalier et al. [85] Chevalier et al. [87] Mondragon et al. [89] Anoop et al. [90] Tseng and Wu [91] Tseng and Wu [92] Prasher et al. [93] Anoop et al. [94]

Gallego et al. [95] Aladag et al. [96] Chang et al. [97] Kwak and Kim [98] Namburu et al. [99] Naik et al. [100] Pastoriza et al. [101]

Chen et al. [117] Yu et al. [118] Chen et al. [119]

A.K. Sharma et al. / Renewable and Sustainable Energy Reviews 53 (2016) 779–791

789

Table 4 (continued ) Nanoparticle/base fluid

Particle size (nm)

Nanoparticle shape

Rheological behaviour

References

CaCO3/distilled water MgO/EG Gold/water Carbon black powder (N115)/EG Fe3O4/deionized water

Length¼ 100 20–50 20 10, 20, 50 20  10

Spherical Spherical Spherical Spherical

Tao et al. [120] Xie et al. [121] Abdelhalim et al. [122] Meng et al. [123] Hong et al. [126]

Fe2O3/EG α-Fe2O3/glycerol

297 18 26

Spherical Spherical

Newtonian Newtonian Newtonian Shear thinning Newtonian for low conc. and Shear thinning for high conc. Shear thinning Shear thinning

*

Gallego et al. [129] Abareshi et al. [130]

not mentioned.

 With the application of external magnetic field, nanofluid shows a deviation in rheological behaviour from Newtonian to non-Newtonian.

4. Recommendations for future work Researchers so far have given more attention to nanofluids containing a single nanoparticle while few studies have been carried out on hybrid nanofluids. Therefore, further investigations can be attempted focussing on combinations of different nanoparticles (i.e., hybrid nanoparticles). The authors have investigated the influence of a few parameters, such as, nanoparticle shape, size, volumetric concentration and shear rate range on the rheological behaviour of nanofluids and have observed some inconsistencies regarding the shape and size of particles. A few researchers have found that while nanofluids containing spherical nanoparticles can exhibit both types of behaviour (i.e., Newtonian and non-Newtonian), nanofluids with tubular-shape particles exhibit non-Newtonian behaviour. These findings can further be advanced by unfolding the influence of nanoparticle shape and size on rheological behaviour with more quality work in future. The optimization of the above mentioned parameters can also be carried out for various nanofluids which may be helpful in synthesizing a new class of nanofluids with better rheological properties. Sidik et al. [136] reviewed literature on challenges of nanofluids and observed that it is unavoidable to prevent sedimentation of particles without using surfactants. For better understanding of the influence of surfactants in nanofluids, it is necessary to carry on quality investigations further.

References [1] Reddy NSK, Rao PV. Experimental investigation to study the effect of solid lubricants on cutting forces and surface quality in end milling. Int J Mach Tool Manuf 2006;46:189–98. [2] Park KH, Ewald B, Kwon PY. Effect of nano-enhanced lubricant in minimum quantity lubrication balling milling. J Tribol 2011;133:031803. [3] Sarhan AAD, Sayuti M, Hamidi M. Reduction of power and lubricant oil consumption in milling process using a new SiO2 nano lubrication system. Int J Adv Manuf Technol 2012;63:505–12. [4] Sayuti M, Sarhan AAD, Tanaka T, Hamdi M, Saito Y. Cutting force reduction and surface quality improvement in machining of aerospace duralumin AL2017-T4 using carbon onion nanolubrication system. Int J Adv Manuf Technol 2013;65:1493–500. [5] Rahmati B, Sarhan AAD, Sayuti M. Morphology of surface generated by end milling AL6061-T6 using molybdenum disulfide (MoS2) nanolubrication in end milling machining. J Clean Prod 2013;66:685–91. [6] Sayuti M, Erh OM, Sarhan AAD, Hamidi M. Investigation on the morphology of the machined surface in end milling of aerospace AL6061-T6 for novel uses of SiO2 nanolubrication system. J Clean Prod 2013;66:655–63. [7] Sayuti M, Sarhan AAD, Hamdi M. An investigation of optimum SiO2 nanolubrication parameters in end milling of aerospace Al6061-T6 alloy. Int J Adv Manuf Technol 2013;67:833–49.

[8] Rahmati B, Sarhan AAD, Sayuti M. Investigating the optimum molybdenum disulfide (MoS2) nanolubrication parameters in CNC milling of AL6061-T6 alloy. Int J Adv Manuf Technol 2014;70(5–8):1143–55. [9] Shen B, Malshe AP, Kalita P, Shih AJ. Performance of novel MoS2 nanoparticles based grinding fluids in minimum quantity lubrication grinding. In: Proceedings of the trans NAMRI/SME, 36. 2008. p. 357–64. [10] Shen B, Shih AJ, Tung SC. Application of nanofluids in minimum quantity lubrication grinding. Tribol Trans 2008;51:730–7. [11] Alberts M, Kalaitzidou K, Melkote S. An investigation of graphite nanoplatelets as lubricant in grinding. Int J Mach Tool Manuf 2009;49:966–70. [12] Prabhu S, Vinayagam BK. Nano surface generation of grinding process using carbon nano tubes. Sadhana 2010;35(6):747–60. [13] Lee PH, Nam JS, Li C, Lee SW. An experimental study on micro-grinding process with nanofluid minimum quantity lubrication (MQL). Int J Precis Eng Manuf 2012;13(3):331–8. [14] Kalita P, Malshe AP, Kumar SA, Yoganath VG, Gurumurthy T. Study of specific energy and friction coefficient in minimum quantity lubrication grinding using oil-based nanolubricants. J Manuf Processes 2012;14:160–6. [15] Kalita P, Malshe AP, Rajurkar KP. Study of tribo-chemical lubricant film formation during application of nanolubricants in minimum quantity lubrication (MQL) grinding. CIRP Ann Manuf Technol 2012;61:327–30. [16] Mao C, Tang X, Zou H, Huang X, Zhou Z. Investigation of grinding characteristic using nanofluid minimum quantity lubrication. Int J Precis Eng Manuf 2012;13(10):1745–52. [17] Mao C, Zou H, Huang X, Zhang J, Zhou Z. The influence of spraying parameters on grinding performance for nanofluid minimum quantity lubrication. Int J Adv Manuf Technol 2013;64:1791–9. [18] Mao C, Zhang J, Huang Y, Zou H, Huang X, Zhou Z. Investigation on the effect of nanofluid parameters on MQL grinding. Mater Manuf Process 2013;28 (4):436–42. [19] Nama JS, Lee PH, Lee SW. Experimental characterization of micro-drilling process using nanofluid minimum quantity lubrication. Int J Mach Tool Manuf 2011;51:649–52. [20] Krishna PV, Srikant RR, Rao DN. Experimental investigation on the performance of nanoboric acid suspensions in SAE-40 and coconut oil during turning of AISI 1040 steel. Int J Mach Tool Manuf 2010;50:911–6. [21] Yan J, Zhang Z, Kuriyagawa T. Effect of nanoparticle lubrication in diamond turning of reaction-bonded SiC. Int J Autom Technol 2011;5(3):307–12. [22] Khandekar S, Sankar MR, Agnihotri V, Ramkumar J. Nano-cutting fluid for enhancement of metal cutting performance. Mater Manuf Processes 2012;27 (9):963–7. [23] Sayuti M, Sarhan AAD, Salem F. Novel uses of SiO2 nano-lubrication system in hard turning process of hardened steel AISI4140 for less tool wear, surface roughness and oil consumption. J Clean Prod 2014;67:265–76. [24] Sharma AK, Tiwari AK, Dixit AR. Progress of nanofluid application in machining: a review. Mater Manuf Processes 2015;30(7):813–28. [25] Choi SUS. Enhancing thermal conductivity of fluids with nanoparticles. In: Proceedings of the ASME 1995. FED 231, MD 66. p. 99-105. [26] Masuda H, Ebata A, Teramae K, Hishiunma N. Alteration of thermal conductivity and viscosity of liquid by dispersed by ultra fine particles (dispersion of Al2O3 SiO2 and TiO2 ultra fine particles). Netsu Bussei 1993;4:227–33. [27] Murshed SMS, Leong KC, Yang C. Investigation of thermal conductivity and viscosity of nano fluids. Int J Therm Sci 2008;47:560–8. [28] Ettefaghi E, Rashidi A, Ahmadi H, Mohtasebi SS, Pourkhalil M. Thermal and rheological properties of oil-based nanofluids from different carbon nanostructures. Int Commun Heat Mass 2013;48:178–82. [29] Wang XQ, Majumdar AS. A review on nanofluids- part II: experiments and applications. Braz J Chem Eng 2008;25(4):631–48. [30] Qiang L, Yimin X. Convective heat transfer and flow characteristics of Cuwater nanofluid. Sci China Ser E 2002;45(4):408–16. [31] Choi SUS, Zhang ZG, Yu W, Lockwood FE, Grulke EA. Anomalous thermal conductivity enhancement in nanotube suspensions. Appl Phys Lett 2001;79 (14):2252–4. [32] Kakac S, Pramuanjaroenkij A. Review of convective heat transfer enhancement with nanofluids. Int J Heat Mass Transf 2009;52:3187–96. [33] Trisaksri V, Wongwises S. Critical review of heat transfer characteristics of nanofluids. Renew Sustain Energy Rev 2007;11:512–23.

790

A.K. Sharma et al. / Renewable and Sustainable Energy Reviews 53 (2016) 779–791

[34] Nasiri A, Niasar MS, Rashidi AM, Khodafarin R. Effect of CNT structures on thermal conductivity and stability of nanofluid. Int J Heat Mass Transf 2012;55:1529–35. [35] Lee JH, Hwang KS, Jang SP, Lee BH, Kim JH, Choi SUS, Choi CJ. Effective viscosities and thermal conductivities of aqueous nanofluids containing low volume concentrations of Al2O3 nanoparticles. Int J Heat Mass Transf 2008;51:2651–6. [36] Tiwari AK, Ghosh P, Sarkar J. Performance comparison of the plate heat exchanger using different nanofluids. Exp Therm Fluid Sci 2013;49:141–51. [37] Murshed SMS, Leong KC, Yang C. Enhanced thermal conductivity of TiO2water based nanofluids. Int J Therm Sci 2005;44:367–73. [38] Eastman JA, Choi SUS, Li S, Yu W, Thompson LJ. Anomalously increased effective thermal conductivities of ethylene glycol-based nanofluids containing copper nanoparticles. Appl Phys Lett 2001;78(6):718–20. [39] Tiwari AK, Ghosh P, Sarkar J, Dahiya H, Parekh J. Numerical investigation of heat transfer and fluid flow in plate heat exchanger using nanofluids. Int J Therm Sci 2014;85:93–103. [40] Saidur R, Leong KY, Mohammad HA. A review on applications and challenges of nanofluids. Renew Sustain Energy Rev 2011;15:1646–68. [41] Wang XQ, Majumdar SA. Heat transfer characteristics of nanofluids: a review. Int J Therm Sci 2007;46:1–19. [42] Godson L, Raja B, Lal DM, Wongwises S. Enhancement of heat transfer using nanofluids-an overview. Renew Sustain Energy Rev 2010;14:629–41. [43] Chang TB, Syu SC, Yang YK. Effects of particle volume fraction on spray heat transfer performance of Al2O3-water nanofluid. Int J Heat Mass Transf 2012;55:1014–21. [44] Sarkar J. A critical review on convective heat transfer correlations of nanofluids. Renew Sustain Energy Rev 2011;15:3271–7. [45] Daungthongsuk W, Wongwises S. A critical review of convective heat transfer of nanofluids. Renew Sustain Energy Rev 2007;11:797–817. [46] Tiwari AK, Ghosh P, Sarkar J. Heat transfer and pressure drop characteristics of CeO2/water nanofluid in plate heat exchanger. Appl Therm Eng 2013;57:24–32. [47] Tiwari AK, Ghosh P, Sarkar J. Investigation of thermal conductivity and viscosity of nanofluids. J Environ Res Dev 2012;7(2):768–77. [48] Vajjha RS, Das DK. A review and analysis on influence of temperature and concentration of nanofluids on thermophysical properties, heat transfer and pumping power. Int J Heat Mass Transf 2012;55:4063–78. [49] Duangthongsuk W, Wongwises S. An experimental study on the heat transfer performance and pressure drop of TiO2-water nanofluids flowing under a turbulent flow regime. Int J Heat Mass Transf 2010;53:334–44. [50] Celen A, Kayaci N, Cebi A, Demir H, Dalkihc AS, Wongwises S. Numerical investigation for the calculation of TiO2–water nanofluids' pressure drop in plain and enhanced pipes. Int Commun Heat Mass 2014;53:98–108. [51] Heyhat MM, Kowsary F, Rashidi AM, Momenpour MH, Amrollahi A. Experimental investigation of laminar convective heat transfer and pressure drop of water-based Al2O3 nanofluids in fully developed flow regime. Exp Therm Fluid Sci 2013;44:483–9. [52] Abad MTJ, Zamzamian A, Dehghan M. Experimental studies on the heat transfer and pressure drop characteristics of Cu-water and Al-water nanofluids in a spiral coil. Exp Therm Fluid Sci 2013;47:206–12. [53] Bayat J, Nikseresht AH. Thermal performance and pressure drop analysis of nanofluids in turbulent forced convective flows. Int J Therm Sci 2012;60:236–43. [54] Madhesh D, Parameshwaran R, Kalaiselvam S. Experimental investigation on convective heat transfer and rheological characteristics of Cu–TiO2 hybrid nanofluids. Exp Therm Fluid Sci 2014;52:104–15. [55] Arani AAA, Amani J. Experimental study on the effect of TiO2-water nanofluid on heat transfer and pressure drop. Exp Therm Fluid Sci 2012;42:107– 15. [56] Heine DR, Petersen MK, Grest GS. Effect of particle shape and charge on bulk rheology of nanoparticle suspensions. J Chem Phys 2010;132(184509):1–6. [57] Chen H, Ding Y. Heat transfer and rheological behaviour of nanofluids-a review. Adv Transp Phenom 2009;1:135–77. [58] Wang X, Xu X, Choi SUS. Thermal conductivity of nanoparticle-fluid mixture. J Thermophys Heat Transf 1999;13:474–80. [59] Das SK, Putra N, Thiesen P, Roetzel W. Temperature dependence of thermal conductivity enhancement for nanofluids. J Heat Transf 2003;125:567–74. [60] Song P, Witharana S, Ding Y. Structure-property relationships for nanofluids. In: Proceedings of the 3rd micro and nano flows conference, Greece. 2011. p. 1–7. [61] Baghbanzadeh M, Rashidi A, Soleimanisalim AH, Rashtchian D. Investigating the rheological properties of nanofluids of water/hybrid nanostructure of spherical silica/MWCNT. Thermochim Acta 2014;578:53–8. [62] Richmond WR, Jones RL, Fawell PD. The relationship between particle aggregation and rheology in mixed silica–titania suspensions. Chem Eng J 1998;71:67–75. [63] Tseng WJ, Lin KC. Rheology and colloidal structure of aqueous TiO2 nanoparticle suspensions. Mater Sci Eng 2003;A355:186–92. [64] He Y, Jin Y, Chen H, Ding Y, Cang D, Lu H. Heat transfer and flow behaviour of aqueous suspensions of TiO2 nanoparticles (nanofluids) flowing upward through a vertical pipe. Int J Heat Mass Transf 2007;50:2272–81. [65] Chen H, Ding Y, Tan C. Rheological behaviour of nanofluids. New J Phys 2007;9:367. [66] Chen H, Ding Y, He Y, Tan C. Rheological behaviour of ethylene glycol based titania nanofluids. Chem Phys Lett 2007;444:333–7.

[67] Chen H, Yang W, He Y, Ding Y, Zhang L, Tan C, Lapkin AA, Bavykin DV. Heat transfer and flow behaviour of aqueous suspensions of titanate nanotubes (nanofluids). Powder Technol 2008;183:63–72. [68] Chen H, Witharana S, Jin Y, Kim C, Ding Y. Predicting thermal conductivity of liquid suspensions of nanoparticles (nanofluids) based on rheology. Particuology 2009;7:151–7. [69] Turgut A, Tavman I, Chirtoc M, Schuchmann HP, Sauter C, Tavman S. Thermal conductivity and viscosity measurements of water based TiO2 nanofluids. Int J Thermophys 2009;30:1213–26. [70] Alphonse P, Bleta R, Soules R. Effect of PEG on rheology on stability of nanocrystalline titania hydrosols. J Colloid Interf Sci 2009;337:81–7. [71] Penkavova V, Tihon J, Wein O. Stability and rheology of dilute TiO2-water nanofluids. Nanoscale Res Lett 2011;6:273. [72] Hojjat M, Etemad SG, Bagheri R, Thibault J. Rheological characteristics of non-Newtonian nanofluids: experimental investigation. Int Commun Heat Mass Transf 2011;38:144–8. [73] Cabaleiro D, Gallego MJP, Fernandez CG, Pineiro MM, Lugo L. Rheological and volumetric properties of TiO2–ethylene glycol nanofluids. Nanoscale Res Lett 2013;8:286. [74] Potschke P, Fornes TD, Paul DR. Rheological behaviour of multiwalled carbon nanotube/polycarbonate composites. Polymer 2002;43:3247–55. [75] Yang Y, Grulke EA, Zhang ZG, Wu G. Thermal and rheological properties of carbon nanotube in oil dispersions. J Appl Phys 2006;99(114307):1–8. [76] Seyhan AT, Gojny FH, Tanoglu M, Schulte K. Rheological behaviour of carbon nanotube/vinyl ester-polyster suspensions and their composites. Eur Polym J 2007;43:2836–47. [77] Yang Y, Grulke EA, Zhang G, Wu G. Temperature effects on the rheological properties of carbon nanotube-in-oil dispersions. Colloid Surf A 2007;298:216–24. [78] Lu K. Rheological behaviour of carbon nanotube-alumina nanoparticle dispersion systems. Powder Technol 2007;177:154–61. [79] Wang B, Wang X, Lou W, Hao J. Rheological and tribological properties of ionic liquid-based nanofluids containing multi-walled carbon nanotubes. J Phys Chem C 2010;114:8749–54. [80] Phuoc TX, Massoudi M, Chen RH. Viscosity and thermal conductivity of nanofluids containing multi-walled carbon nanotubes stabilized by chitosan. Int J Therm Sci 2011;50:12–8. [81] Meng Z, Wu D, Wang L, Zhu H, Li Q. Carbon nanotube glycol nanofluids: photo-thermal properties, thermal conductivities and rheological behaviour. Particuology 2012;10:614–8. [82] Ruan B, Jacobi AM. Ultrasonication effects on thermal and rheological properties of carbon nanotube suspensions. Nanoscale Res Lett 2012;7:127. [83] Wang J, Zhu J, Zhang X, Chen Y. Heat transfer and pressure drop of nanofluids containing carbon nanotubes in laminar flows. Exp Therm Fluid Sci 2013;44:716–21. [84] Ko GH, Heo K, Lee K, Kim DS, Kim C, Sohn Y, Choi M. An experimental study on the pressure drop of nanofluids containing carbon nanotubes in a horizontal tube. Int J Heat Mass Transf 2007;50:4749–53. [85] Chevalier J, Tillement O, Ayela F. Rheological properties of nanofluids flowing through microchannels. Appl Phys Lett 2007;91:233103. [86] Tavman I, Turgut A, Chirtoc M, Schuchmann HP, Tavman S. Experimental investigation of viscosity and thermal conductivity of suspensions containing nanosized ceramic particles. Arch Mater Sci Eng 2008;34(2):99–104. [87] Chevalier J, Tillement O, Ayela F. Structure and rheology of SiO2 nanoparticle suspensions under very high shear rates. Phys Rev E 2009;80:051403. [88] Jung Y, Son YH, Lee JK, Phuoc TX, Soong Y, Chyu MK. Rheological behaviour of clay-nanoparticle hybrid-added bentonite suspensions: specific role of hybrid additives on the gelation of clay-based fluids. ACS Appl Mater Interfaces 2011;3:3515–22. [89] Mondragon R, Julia JE, Barba A, Jarque JC. Determination of packing fraction of silica nanoparticles from the rheological and viscoelastic measurements of nanofluids. Chem Eng Sci 2012;80:119–27. [90] Anoop K, Sadr R, Jubouri MA, Amani M. Rheology of mineral oil-SiO2 nanofluids at high pressure and high temperatures. Int J Therm Sci 2014;77:108–15. [91] Tseng WJ, Wu CH. Aggregation, rheology and electrophoretic packing structure of aqueous Al2O3 nanoparticle suspensions. Acta Mater 2002;50:3757–66. [92] Tseng WJ, Wu CH. Sedimentation, rheology and particle-packing structure of aqueous Al2O3 suspensions. Ceram Int 2003;29:821–8. [93] Prasher R, Song D, Wang J, Phelan P. Measurements of nanofluid viscosity and its implications for thermal applications. Appl Phys Lett 2006;89:133108. [94] Anoop KB, Kabelac S, Sundararajan T, Das SK. Rheological and flow characteristics of nanofluids: influence of electroviscous effects and particle agglomeration. J Appl Phys 2009;106:034909. [95] Gallego MJP, Lugo L, Legido JL, Pineiro MM. Thermal conductivity and viscosity measurements of ethylene glycol-based Al2O3 nanofluids. Nanoscale Res Lett 2011;6:221. [96] Aladag B, Halelfadl S, Doner N, Mare T, Duret S, Estelle P. Experimental investigations of the viscosity of nanofluids at low temperatures. Appl Energy 2012;97:876–80. [97] Chang H, Jwo CS, Lo CH, Tsung TT, Kao MJ, Lin HM. Rheology of CuO nanoparticle suspension prepared by ASNSS. Rev Adv Mater Sci 2005;10:128–32. [98] Kwak K, Kim C. Viscosity and thermal conductivity of copper oxide nanofluid dispersed in ethylene glycol. Korea-Aust Rheol J 2005;17(2):35–40.

A.K. Sharma et al. / Renewable and Sustainable Energy Reviews 53 (2016) 779–791

[99] Namburu PK, Kulkarni DP, Misra D, Das DK. Viscosity of copper oxide nanoparticles dispersed in ethylene glycol and water mixture. Exp Therm Fluid Sci 2007;32:397–402. [100] Naik MT, Janardhana GR, Reddy KVK, Reddy BS. Experimental investigation into rheological property of copper oxide nanoparticles suspended in propylene glycol–water based fluids. ARPN J Eng Appl Sci 2010;5(6):29–34. [101] Gallego MJ, Casanova C, Legido JL, Pineiro MM. CuO in water nanofluid: influence of particle size and polydispersity on volumetric behaviour and viscosity. Fluid Phase Equilib 2011;300:188–96. [102] Saedinia M, Behabadi MAK, Razi P. Thermal and rheological characteristics of CuO-base oil nanofluid flow inside a circular tube. Int Commun Heat Mass Transf 2012;39:152–9. [103] William JKM, Ponmani S, Samuel R, Nagarajan R, Sangwai JS. Effect of CuO and ZnO nanofluids in xanthan gum on thermal, electrical and high pressure rheology of water-based drilling fluids. J Petrol Sci Eng 2014;117:15–27. [104] Tseng WJ, Li SY. Rheology of colloidal BaTiO3 suspension with ammonium polyacrylate as a dispersant. Mater Sci Eng A 2002;333:314–9. [105] Tseng WJ, Lin CL. Effects of dispersants on rheological behaviour of BaTiO3 powders in ethanol–isopropanol mixtures. Mater Chem Phys 2003;80:232–8. [106] Tseng WJ, Chen CN. Effect of polymeric dispersant on rheological behaviour of nickel-terpineol suspensions. Mater Sci Eng A 2003;347:145–53. [107] Tseng WJ, Chen CN. Dispersion and rheology of nickel nanoparticle inks. J Mater Sci 2006;41:1213–9. [108] Mary B, Dubois C, Carreau PJ, Brousseau P. Rheological properties of suspensions of polyethylene-coated aluminium nanoparticles. Rheol Acta 2006;45:561–73. [109] Tiepel U, Barth UF. Rheology of suspensions with aluminium nano-particles. JATM 2009;1(1):43–7. [110] Tamjid E, Guenther BH. Rheology and colloidal structure of silver nanoparticles dispersed in diethylene glycol. Powder Technol 2010;197:49–53. [111] Chen CN, Huang CT, Tseng WJ, Wei MH. Dispersion and rheology of surfactant-mediated silver nanoparticle suspensions. Appl Surf Sci 2010;257:650–5. [112] Wang B, Wang X, Lou W, Hao J. Thermal conductivity and rheological properties of graphite/oil nanofluids. Colloid Surf A 2012;414:125–31. [113] Duan F, Wong TF, Crivoi A. Dynamic viscosity measurement in nonNewtonian graphite nanofluids. Nanoscale Res Lett 2012;7:360. [114] Moghaddam MB, Goharshadi EK, Entezari MH, Nancarrow P. Preparation, characterization and rheological properties of grapheme–glycerol nanofluids. Chem Eng J 2013;231:365–72. [115] Mehrali M, Sadeghinezhad E, Latibari ST, Kazi SN, Mehrali M, MNBM Zubir. Metselaar HSC. Investigation of thermal conductivity and rheological properties of nanofluids containing grapheme nanoplatelets. Nanoscale Res Lett 2014;9:15. [116] Tseng WJ, Tzeng F. Effect of ammonium polyacrylate on dispersion and rheology of aqueous ITO nanoparticle colloids. Colloid Surf A 2006;276:34–9. [117] Chen H, Ding Y, Lapkin A. Rheological behaviour of nanofluids containing tube/rod-like nanoparticles. Powder Technol 2009;194:132–41. [118] Yu W, Xie H, Chen L, Li Y. Investigation of thermal conductivity and viscosity of ethylene glycol based ZnO nanofluid. Thermochim Acta 2009;491:92–6. [119] Chen H, Ding Y, Lapkin A, Fan X. Rheological behaviour of ethylene glycoltitanate nanotube nanofluids. J Nanopart Res 2009;11:1513–20. [120] HaiTao Z, ChangJiang L, DaXiong W, CanYing Z, Yansheng Y. Preparation, characterization, viscosity and thermal conductivity of CaCO3 aqueous nanofluids. Sci China Technol Sci 2010;53(2):360–8. [121] Xie H, Yu W, Chen W. MgO nanofluids: higher thermal conductivity and lower viscosity among ethylene glycol-based nanofluids containing oxide nanoparticles. J Exp Nanosci 2010;5(5):463–72.

791

[122] Abdelhalim MAK, Mady MM, Ghannam MM. Rheological and dielectric properties of different gold nanoparticle sizes. Lipids Health Dis 2011;10:208. [123] Meng Z, Han D, Wu D, Zhu H, Li Q. Thermal conductivities, rheological behaviours and photo thermal properties of ethylene glycol-based nanofluids containing carbon black nanoparticles. Proc Eng 2012;36:521–7. [124] Cholewa M, Zyla G, Witek A, Plog JP, Lehmann V, Oerther T, Gross D. Viscosity of Yttrium oxide (Y2O3) and magnesium-aluminum spinel (MgAl2O4) nanopowder suspensions in ethyl alcohol. Arch Mech 2013;65(2):131–42. [125] Hong RY, Ren ZQ, Han P, Li HZ, Zheng Y, Ding J. Rheological properties of water-based Fe3O4 ferrofluids. Chem Eng Sci 2007;62:5912–24. [126] Hong RY, Pan TT, Han YP, Li HZ, Ding J, Han S. Magnetic field synthesis of Fe3O4 nanoparticle used as a precursor of ferrofluids. J Magn Magn Mater 2007;310:37–47. [127] Wei JH, Leng CJ, Zhang XZ, Li WH, Liu ZY, Shi J. Synthesis and magnetorheological effect of Fe3O4–TiO2 nanocomposite. J Phys Conf 2009;149:012083. [128] Phuoc TX, Massoudi M. Experimental observations of the effects of shear rates and particle concentration on the viscosity of Fe2O3-deionized water nanofluids. Int J Therm Sci 2009;48:1294–301. [129] Gallego MJP, Lugo L, Legido JL, Pineiro MM. Rheological non-Newtonian behaviour of ethylene glycol-based Fe2O3 nanofluids. Nanoscale Res Lett 2011;6:560. [130] Abareshi M, Sajjadi SH, Zebarjad SM, Goharshadi EK. Fabrication, characterization and measurement of viscosity of α-Fe2O3-glycerol nanofluids. J Mol Liq 2011;163:27–32. [131] Resiga DS, Socoliuc V, Boros T, Borbath T, marinica O, Han A, Vekas L. The influence of particle clustering on the rheological properties of highly concentrated magnetic nanofluids. J Colloid Interfaces Sci 2012;373:110–5. [132] Katiyar A, Singh AN, Shukla P, Nandi T. Rheological behaviour of magnetic nanofluids containing spherical nanoparticles of Fe–Ni. Powder Technol 2012;224:86–9. [133] Moattar MTZ, Cegincara RM. Stability, rheological, magnetorheological and volumetric characterizations of polymer based magnetic nanofluids. Colloid Polym Sci 2013;291:1977–87. [134] Vekas L, Marinica O, Resiga DS, Stoian FD, Bica D. Magnetic and flow properties of high magnetization nanofluids. In: Proceedings of the 6th international conference on hydraulic machinery and hydrodynamics, HMH2004 Romania. 2004. p. 685–92. [135] Vekas L, Rasa M, Bica D. Physical properties of magnetic fluids and nanoparticles from magnetic and magneto-rheological measurements. J Colloid Interfaces Sci 2000;231:247–54. [136] Sidik NAC, Mohammed HA, Alawi OA, Samion S. A review on preparation methods and challenges of nanofluids. Int Commun Heat Mass Transf 2014;54:115–25. [137] Wang L, Chen H, Witharana S. Rheology of nanofluids: a review. Recent Pat Nanotechnol 2013;7(3):232–46. [138] Chen L, Xie H, Yu W, Li Y. Rheological behaviors of nanofluids containing multi-walled carbon nanotube. J Dispers Sci Technol 2011;32(4):550–4. [139] Yu W, France DM, Routbort JL, Choi SUS. Review and Comparison of Nanofluid Thermal Conductivity and Heat Transfer Enhancements. Heat Transsf Eng 2008;29(5):432–60. [140] Verma SK, Tiwari AK. Progress of nanofluid application in solar collectors: a review. Energy Convers Manag 2015;100:324–46. [141] Tiwari AK, Ghosh P, Sarkar J. Particle concentration levels of various nanofluids in plate heat exchanger for best performance. Int J Heat Mass Transf 2015;89:1110–8.