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Viscosity characteristics of water based magnetic fluids mixing a water soluble polymer
Physics Procedia 9 (2010) 117–120 Physics Procedia 00 (2009) 000±000
www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia
12th International Conference on Magnetic Fluids
Viscosity characteristics of water based magnetic fluids mixing a water soluble polymer Shigemitsu Shuchia,*, Hiroshi Yamaguchib1 a
Akita Prefectural University, 84-4 Tsuchiya Ebinokuchi, Yurihonjyo, Akita 015-0055, JAPAN b Doshisha University, 1-3 Tatara Miyakotani, Kyotanabe, Kyoto 610-0394, JAPAN Elsevier use only: Received date here; revised date here; accepted date here
Abstract Viscosity of water based magnetic fluid and polymer mixed magnetic fluids is measured by using a cone-and-plate viscometer with applying magnetic field from the bottom of the plate. As the result, effect of structural viscosity (shear thinning) of polymer solution is observed despite of magnetic field. Furthermore it was also observed that viscosity of polymer mixed magnetic fluid is slightly decreased by applying magnetic field for wide range of shear rate. c 2010 Published by Elsevier Ltd
Keywords: Magnetic fluid; Polymer solution; Structural viscosity; Cone-and-plate viscometer
1. Introduction "Functional fluids" is a word that indicates a group of fluids that have some functions in the fluid itself. Magnetic fluid, a typical functional fluid, acts like a fluid that has magnetization in itself. The typical characteristic of magnetic fluid is an increase of apparent viscosity with applying magnetic field. Polymeric liquids, as another functional fluid, change its viscosity with change of share rate of flow (structural viscosity). Furthermore polymeric liquids have elasticity, so that present some interesting phenomena when it flow [1]. To mix these fluids, it is expected that a functional fluid has magneto-viscous effect and structural viscosity would be obtained. Besides many applications would be expected by mixing polymers having several characteristics to magnetic fluid. For example, a new power generation system using electro-conductive polymer was investigated by Yamaguchi, et al. [2]. In this study, a new functional fluid mixing a water soluble polymer (polyacrylamide) with water based magnetic fluid. With the fluid, viscoelasticity controlled by external magnetic field would be expected. In this report, as a preconsideration, viscosity characteristics of the fluids are investigated.
* Corresponding author. Tel.: +81-184-272214; fax: +81-184-272188. E-mail address: [email protected]..
c 2010 Published by Elsevier Ltd 1875-3892 doi:10.1016/j.phpro.2010.11.028
118
S. Shuchi, H. Yamaguchi / Physics Procedia 9 (2010) 117–120 Shigemitsu Shuchia / Physics Procedia 00 (2010) 000±000
2. Test fluid and experimental setup In this study, a water based magnetic fluid (W-40 by Taiho Kougyou, ltd.) and a polymer additive, polyacrylamide (AH-120P, Sanyo Chemical Industries, ltd.) are used. 3 types of test fluids are prepared. One is a magnetic fluid, the other two are polymer mixed magnetic fluid with the mixing ratio 0.06 and 0.12 wt% respectively. In preparation, the magnetic fluid and the polymer are mixed as in prescribed ratio then it is shaken by a homogenizer in several minutes just before a measurement. Figure 1 shows experimental apparatus used in this study. Cone-and-plate viscometer [3] is used to measure viscosity. The diameter and cone angle of the cone are 90 mm and 174 degree respectively. In measurement, a test fluid is filled in the gap between the cone and the plate made of aluminum alloy. The cone is rotated by a motor connected through a torque meter that measure torque to rotate the cone so that shear stress yielding in test fluids in the gap can be calculated. In the experiment, shear rate applied to test fluids is from 284 to 852 1/s. Magnetic field is applied by an external magnet located under the plate. The magnetic field distribution applied to test fluids is indicated in figure 2 and figure 3. In figure 2, magnetic field distribution from the top of the plate (z=0 mm) to the surface of the cone (z=3.5 mm) is almost the same though it is not uniform in r-direction. Magnetic field intensity is about 27 mT on the center of surface of the plate. The temperature of test fluids was kept by a circulator as 15±1 Celsius degree through the experiment.
ԘCone & plate ԙTorque detector ԚTorque meter ԛRecorder ԜPC ԝDC motor
ԞSpeed controller ԟSpeed indicator ԠCirculator ԡMonitor ԢPermanent magnet ԣHeight controller
Figure 1. Experimental Apparatus
S. Shuchi, H. Yamaguchi / Physics Procedia 9 (2010) 117–120 Shigemitsu Shuchia / Physics Procedia 00 (2010) 000±000
119
Magnetic flux density Hz [mT]
30
25
20
15 0.0 0.5 2.0 2.5 3.0 3.5
10
5
0 0
10
20
30 40 Radius r [mm]
50
60
Figure 2. Magnetic field distribution (Hz)
Magnetic flux density Hr [mT]
30
0.0 0.5 2.0 2.5 3.0 3.5
25
20
15
10
5
0 0
10
20
30 40 Radius r [mm]
50
60
Figure 3. Magnetic field distribution (Hr)
3. Results and Discussion Figure 4 shows the results of no magnetic field case. Viscosity of magnetic fluid (W-40) is almost the same in the experimental condition, hence the magnetic fluid would be considered as a Newtonian fluid. The averaged viscosity of the magnetic fluid was 2.310-2 Pas. On the other hand, for polymer mixed magnetic fluids (W-40+PAA0.06, W-40+PAA0.12), viscosity becomes higher than original magnetic fluid in totally. The effect depends on the mixing ratio of the polymer and the averaged rate of increase are 153% and 20% respectively. Besides viscosity of the polymer mixed magnetic fluids is decreased with increase of shear rate by effect of structural viscosity (shear thinning). For W-40+PAA0.12, the rate of change is about -22% from 284 to 852 1/s. Figure 5 shows the results of applying magnetic field case. In the result, viscosity becomes larger for magnetic fluid in comparison with no magnetic field case. The averaged rate of change is about +3%. For polymer mixed magnetic fluids, viscosity is decreased with increase of shear rate similarly to no magnetic field case. For W40+PAA0.12, the rate of change is about -25% from 284 to 852 1/s. Furthermore, it is also decreased by applying magnetic field. The averaged rate of change is about -3% for all cases. Thus viscosity increase by mixing polymer to magnetic fluid is reduced. In this case, the rates of increase are 137% and 185% respectively. However the reason of such decrease by applying magnetic field to the polymer mixed magnetic fluids is not cleared in this study.
120
S. Shuchi, H. Yamaguchi / Physics Procedia 9 (2010) 117–120 Shigemitsu Shuchia / Physics Procedia 00 (2010) 000±000
0.10 W-40 W-40+PAA0.06
㪭㫀㫊㪺㫆㫊㫀㫋㫐㩷㪲㪧㪸䍃㫊㪴
0.08
W-40+PAA0.12
0.06 0.04 0.02 0.00 200
400 600 800 Shear rate [1/s]
1000
Figure 4. Viscosity (no magnetic field)
0.10 W-40 W-40+PAA0.06
㪭㫀㫊㪺㫆㫊㫀㫋㫐㩷㪲㪧㪸䍃㫊㪴
0.08
W-40+PAA0.12
0.06 0.04 0.02 0.00 200
400 600 800 Shear rate [1/s]
1000
Figure 5. Viscosity (applying magnetic field)
4. Conclusion Viscosity characteristic of a mixture of a water based magnetic fluid and a polyacrylamide was investigated. As the result, the polymer mixed magnetic fluid showed higher viscosity than that of original magnetic fluid and it was also observed that reduction of viscosity with increase of share rate by the effect of structural viscosity of polymer solution for both no magnetic field case and applying magnetic field case. Additionally, with applying magnetic field, the viscous increase of the mixture was slightly decreased. However the effect of magnetic field to the mixture was not cleared in this study. Furthermore, as a matter of course, measurement of elasticity of the fluid was absent, hence further investigation is required in the future. Acknowledgment This work was supported by Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research(C) 18560181. Reference [1] R.G. Larson, The Structure and Rheology of Complex Fluids, Oxford Univ. Press, 1999. [2] H. Yamaguchi, X.-R. Zhang, S. Higashia, M. Li, J. Magn. Magn. Mater. 320-7(2007) 1406-1411. [3] R.B. Bird, W.E. Stewart, E.N. Lightfoot, Transport Phenomena Second Edition, WILEY, 2002.
www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia
12th International Conference on Magnetic Fluids
Viscosity characteristics of water based magnetic fluids mixing a water soluble polymer Shigemitsu Shuchia,*, Hiroshi Yamaguchib1 a
Akita Prefectural University, 84-4 Tsuchiya Ebinokuchi, Yurihonjyo, Akita 015-0055, JAPAN b Doshisha University, 1-3 Tatara Miyakotani, Kyotanabe, Kyoto 610-0394, JAPAN Elsevier use only: Received date here; revised date here; accepted date here
Abstract Viscosity of water based magnetic fluid and polymer mixed magnetic fluids is measured by using a cone-and-plate viscometer with applying magnetic field from the bottom of the plate. As the result, effect of structural viscosity (shear thinning) of polymer solution is observed despite of magnetic field. Furthermore it was also observed that viscosity of polymer mixed magnetic fluid is slightly decreased by applying magnetic field for wide range of shear rate. c 2010 Published by Elsevier Ltd
Keywords: Magnetic fluid; Polymer solution; Structural viscosity; Cone-and-plate viscometer
1. Introduction "Functional fluids" is a word that indicates a group of fluids that have some functions in the fluid itself. Magnetic fluid, a typical functional fluid, acts like a fluid that has magnetization in itself. The typical characteristic of magnetic fluid is an increase of apparent viscosity with applying magnetic field. Polymeric liquids, as another functional fluid, change its viscosity with change of share rate of flow (structural viscosity). Furthermore polymeric liquids have elasticity, so that present some interesting phenomena when it flow [1]. To mix these fluids, it is expected that a functional fluid has magneto-viscous effect and structural viscosity would be obtained. Besides many applications would be expected by mixing polymers having several characteristics to magnetic fluid. For example, a new power generation system using electro-conductive polymer was investigated by Yamaguchi, et al. [2]. In this study, a new functional fluid mixing a water soluble polymer (polyacrylamide) with water based magnetic fluid. With the fluid, viscoelasticity controlled by external magnetic field would be expected. In this report, as a preconsideration, viscosity characteristics of the fluids are investigated.
* Corresponding author. Tel.: +81-184-272214; fax: +81-184-272188. E-mail address: [email protected]..
c 2010 Published by Elsevier Ltd 1875-3892 doi:10.1016/j.phpro.2010.11.028
118
S. Shuchi, H. Yamaguchi / Physics Procedia 9 (2010) 117–120 Shigemitsu Shuchia / Physics Procedia 00 (2010) 000±000
2. Test fluid and experimental setup In this study, a water based magnetic fluid (W-40 by Taiho Kougyou, ltd.) and a polymer additive, polyacrylamide (AH-120P, Sanyo Chemical Industries, ltd.) are used. 3 types of test fluids are prepared. One is a magnetic fluid, the other two are polymer mixed magnetic fluid with the mixing ratio 0.06 and 0.12 wt% respectively. In preparation, the magnetic fluid and the polymer are mixed as in prescribed ratio then it is shaken by a homogenizer in several minutes just before a measurement. Figure 1 shows experimental apparatus used in this study. Cone-and-plate viscometer [3] is used to measure viscosity. The diameter and cone angle of the cone are 90 mm and 174 degree respectively. In measurement, a test fluid is filled in the gap between the cone and the plate made of aluminum alloy. The cone is rotated by a motor connected through a torque meter that measure torque to rotate the cone so that shear stress yielding in test fluids in the gap can be calculated. In the experiment, shear rate applied to test fluids is from 284 to 852 1/s. Magnetic field is applied by an external magnet located under the plate. The magnetic field distribution applied to test fluids is indicated in figure 2 and figure 3. In figure 2, magnetic field distribution from the top of the plate (z=0 mm) to the surface of the cone (z=3.5 mm) is almost the same though it is not uniform in r-direction. Magnetic field intensity is about 27 mT on the center of surface of the plate. The temperature of test fluids was kept by a circulator as 15±1 Celsius degree through the experiment.
ԘCone & plate ԙTorque detector ԚTorque meter ԛRecorder ԜPC ԝDC motor
ԞSpeed controller ԟSpeed indicator ԠCirculator ԡMonitor ԢPermanent magnet ԣHeight controller
Figure 1. Experimental Apparatus
S. Shuchi, H. Yamaguchi / Physics Procedia 9 (2010) 117–120 Shigemitsu Shuchia / Physics Procedia 00 (2010) 000±000
119
Magnetic flux density Hz [mT]
30
25
20
15 0.0 0.5 2.0 2.5 3.0 3.5
10
5
0 0
10
20
30 40 Radius r [mm]
50
60
Figure 2. Magnetic field distribution (Hz)
Magnetic flux density Hr [mT]
30
0.0 0.5 2.0 2.5 3.0 3.5
25
20
15
10
5
0 0
10
20
30 40 Radius r [mm]
50
60
Figure 3. Magnetic field distribution (Hr)
3. Results and Discussion Figure 4 shows the results of no magnetic field case. Viscosity of magnetic fluid (W-40) is almost the same in the experimental condition, hence the magnetic fluid would be considered as a Newtonian fluid. The averaged viscosity of the magnetic fluid was 2.310-2 Pas. On the other hand, for polymer mixed magnetic fluids (W-40+PAA0.06, W-40+PAA0.12), viscosity becomes higher than original magnetic fluid in totally. The effect depends on the mixing ratio of the polymer and the averaged rate of increase are 153% and 20% respectively. Besides viscosity of the polymer mixed magnetic fluids is decreased with increase of shear rate by effect of structural viscosity (shear thinning). For W-40+PAA0.12, the rate of change is about -22% from 284 to 852 1/s. Figure 5 shows the results of applying magnetic field case. In the result, viscosity becomes larger for magnetic fluid in comparison with no magnetic field case. The averaged rate of change is about +3%. For polymer mixed magnetic fluids, viscosity is decreased with increase of shear rate similarly to no magnetic field case. For W40+PAA0.12, the rate of change is about -25% from 284 to 852 1/s. Furthermore, it is also decreased by applying magnetic field. The averaged rate of change is about -3% for all cases. Thus viscosity increase by mixing polymer to magnetic fluid is reduced. In this case, the rates of increase are 137% and 185% respectively. However the reason of such decrease by applying magnetic field to the polymer mixed magnetic fluids is not cleared in this study.
120
S. Shuchi, H. Yamaguchi / Physics Procedia 9 (2010) 117–120 Shigemitsu Shuchia / Physics Procedia 00 (2010) 000±000
0.10 W-40 W-40+PAA0.06
㪭㫀㫊㪺㫆㫊㫀㫋㫐㩷㪲㪧㪸䍃㫊㪴
0.08
W-40+PAA0.12
0.06 0.04 0.02 0.00 200
400 600 800 Shear rate [1/s]
1000
Figure 4. Viscosity (no magnetic field)
0.10 W-40 W-40+PAA0.06
㪭㫀㫊㪺㫆㫊㫀㫋㫐㩷㪲㪧㪸䍃㫊㪴
0.08
W-40+PAA0.12
0.06 0.04 0.02 0.00 200
400 600 800 Shear rate [1/s]
1000
Figure 5. Viscosity (applying magnetic field)
4. Conclusion Viscosity characteristic of a mixture of a water based magnetic fluid and a polyacrylamide was investigated. As the result, the polymer mixed magnetic fluid showed higher viscosity than that of original magnetic fluid and it was also observed that reduction of viscosity with increase of share rate by the effect of structural viscosity of polymer solution for both no magnetic field case and applying magnetic field case. Additionally, with applying magnetic field, the viscous increase of the mixture was slightly decreased. However the effect of magnetic field to the mixture was not cleared in this study. Furthermore, as a matter of course, measurement of elasticity of the fluid was absent, hence further investigation is required in the future. Acknowledgment This work was supported by Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research(C) 18560181. Reference [1] R.G. Larson, The Structure and Rheology of Complex Fluids, Oxford Univ. Press, 1999. [2] H. Yamaguchi, X.-R. Zhang, S. Higashia, M. Li, J. Magn. Magn. Mater. 320-7(2007) 1406-1411. [3] R.B. Bird, W.E. Stewart, E.N. Lightfoot, Transport Phenomena Second Edition, WILEY, 2002.