SiC纳米粉体悬浮液导热系数研究

STUDY ON THE THERMAL CONDUCTIVITY OF SiC NANOFLUIDS

本工作采用非稳态热丝法 ,测量了水中加平均粒径为 2 5nm的碳化硅粉 (简称n -SiC) ,乙二醇中加n -SiC ,水中加平均粒径为 0 .6μm的碳化硅粉 (简称 μ -SiC)和乙二醇中加 μ -SiC等 4个系列不同固相体积含量悬浮液的有效导热系数。实验结果表明 :对于所研究的悬浮液 ,其有效导热系数相对增加量随固相加入量的增加而线性增加 ;固相颗粒形貌对有效导热系数相对增加量有显著影响 ;基体液体虽对有效导热系数相对增加量无明显影响 。

Nanaofluids are innovative working media with high heat transfer efficiency in thermal system. In the present study, the thermal conductivities of four series of suspensions, which consisted of nano_sized SiC particles with average diameter of 25 nm (n-SiC) in water, n-SiC in ethylene glycol (EG), micro_sized SiC particles with average diameter of 0.6 μm (μ-SiC) in water, and μ-SiC in EG, were measured. The experimental results show that the thermal conductivities of the suspensions increase obviously and the enhancement is proportional to the volume fraction of the solid phase. Although the enhancement percentage is not significantly related to the base fluid, the absolute value is directly determined by the thermal conductivity of the base fluid. The morphologies of the added solid phases play an important role in the enhancement of thermal conductivity of the nanofluid.