Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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A Study on the High Temperature Thermal Conductivity Measurement of Nanofluid Using a Two-Phase Model

2상 모델을 이용한 나노유체의 고온 열전도도 측정 연구

  • Park, Sang-Il (Industrial Energy Efficiency Research Center, Korea Institute of Energy Research) ;
  • Lee, Wook-Hyun (Industrial Energy Efficiency Research Center, Korea Institute of Energy Research)
  • 박상일 (한국에너지기술연구원 산업효율연구센터) ;
  • 이욱현 (한국에너지기술연구원 산업효율연구센터)
  • Published : 2010.02.01
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Abstract

The effective thermal conductivity of two-phase materials such as unbonded silica sands saturated with a nanofluid was measured at high temperature using the transient thermal probe method. The nanofluid used in this study was a water-based mixture of 0.1 vol% $Al_2O_3$ nanoparticles with a diameter of 45 nm. The convection problem for fluids was prevented with this measurement method because the fluid was confined to within very small pore spaces. Based on the prediction model for unbonded sands, the thermal conductivities of the saturating nanofluid at high temperatures could be determined with the measured effective thermal conductivities for the two-phase material. In the results, increases in the thermal conductivity ratios of the nanofluid to pure water when temperatures were varied from $30^{\circ}$ to $80^{\circ}C$ were within the range of 4.87%~5.48%.

나노유체로 기공이 채워진 규사와 같은 2상 물질의 고온에서의 유효 열전도도를 비정상열침법을 사용하여 측정하였다. 본 연구의 나노유체는 물과 0.1% 체적률의 입경이 45 nm 인 알루미나 나노입자의 혼합유체이다. 본 연구의 측정방법은 액체가 모래의 미세한 기공 내에 존재하므로, 열전도도의 측정에서의 액체의 대류에 의한 문제가 적다. 본 연구의 모래에 대한 예측모델을 사용하여 나노유체와 모래입자의 2상 물질의 유효 열전도도의 측정결과로부터, 고온의 나노유체의 열전도도를 결정하였다. 실험결과, $30^{\circ}C\sim80^{\circ}C$의 온도 범위에서 순수한 물에 대한 본 연구의 나노유체의 열전도도의 증가율은 4.87% ~ 5.48% 의 범위에서 변화하는 것으로 나타났다.

Keywords

References

  1. Park, S. I., 1987, "Thermal Conductivities of Bentonite-Bonded Molding Sands at High Temperatures," Ph. D Thesis, Georgia Institute of Technology.
  2. Park, S. I. and Hartley, J. G., 1999, "Predicting Effective Thermal Conductivities of Unbonded and Bonded Silica Sands," J. of Applied Physics, Vol.86, No.9, pp.5263-5269. https://doi.org/10.1063/1.371509
  3. Park, Sang-il, 2005, "A Study on Determination of High Temperature Fluid Thermal Conductivity Using Prediction Model for Sands," Proceedings of the KSME 2005 Fall Annual Meeting, 05F049, pp. 1336-1341.
  4. Li, C. H. and Peterson, G. P., 2007, "The Effect of Particle Size Conductivity of $Al_2O_3$-Water Nanofluids," J. of Applied Physics, Vol.101, 044312. https://doi.org/10.1063/1.2436472
  5. Das, S. K., Putra, N., Thiesen, P. and Roetzel, W., 2003, "Temperature Dependence of Thermal Conductivity Enhancement for Nanofluids," J. of Heat Transfer, Vol.125, pp.567-574. https://doi.org/10.1115/1.1571080
  6. Zhang, X, Gu, H. and Fujii, M., 2007, "Effective Thermal Conductivity and Thermal Diffusivity of Nanofluids Containing Spherical and Cylindrical Nanoparticles," Experimental Thermal and Fluid Science, Vol.31, pp.593-599. https://doi.org/10.1016/j.expthermflusci.2006.06.009

Cited by

  1. An Experimental Study of Transient Hot-wire Sensor Module for Measuring Thermal Diffusivity of Nanofluids vol.35, pp.2, 2011, https://doi.org/10.3795/KSME-B.2011.35.2.113