AN APPROXIMATE CORRELATING METHOD FOR EFFECTIVE THERMAL CONDUCTIVITY OF DILUTE NANOFLUID
An approximate correlating method for the effective thermal conductivity of dilute nanofluid using unsteady state measuring methods is proposed in this paper. This method is based on two assumptions. One assumption is that a nanofluid is a mixture consisting of a continuous base fluid component and a discontinuous nanoparticle component, where the absolute velocity of nanoparticle can be viewed as the sum of the base fluid velocity and a slip velocity between nanoparticle and base fluid. The other assumption is about the critical slip mechanisms in nanofluids. With the critical nanoparticle/fluid slip mechanisms being clarified, which are the Brownian diffusion and thermophoresis of nanoparticles, a realistic two-component transport model for the nanofluids is developed. Then, using the obtained conservation equations for dilute nanofluids and applying the dimensional analysis method, the experimental data of effective thermal conductivity of dilute nanofluids can be correlated to proposed parameters. Further concern about nanoscale size effect of heat carriers on thermal conductivity of nanofluid is also provided. The heat carriers include phonon, electron and photon. Using the proposed approximate correlating method, the data of a nanofluid made by 50nm CuO nanoparticle and ethylene glycol (EG) from our experiments are fitted to get corresponding constants, which relatively give a good match with other researchers’ derivations. Further investigation on different types of nanofluids is needed to study the flexibility of the correlating method.
nanofluid correlation effective thermal conductivity near-field radiation
Leping Zhou Buxuan Wang Xiaoze Du Yongping Yang Yunfang Zhang
School of Energy and Power Key Laboratory of Condition Monitoring and Control for Power Plant Equipm Department of Thermal Engineering Tsinghua University Beijing 100084, China
国际会议
The Ninth Asian Thermophysical Properties Conference(第九届亚洲热物理性能会议 ATPC 2010)
北京
英文
380-388
2010-10-19（万方平台首次上网日期，不代表论文的发表时间）