局部热壁面温度瞬态变化腔体内纳米流体自然对流数值模拟

Numerical Simulation of Nanofluid Natural Convection in Cavity with Transient Variation in Temperature of Local Hot Wall

在腔体下壁面局部热源温度随时间按正弦规律变化的条件下,对二维腔体内Cu-水纳米流体的非稳态自然对流进行了数值研究。在相关参数一定的条件下,研究了瑞利数、纳米颗粒体积分数以及腔体高宽比对自然对流换热特性的影响。计算结果表明:随着瑞利数Ra及纳米颗粒体积分数的增加,腔体壁面的时均传热速率增大,同时随着腔体高宽比D的增加,时均传热速率减小并趋于稳定的值。

Under the condition that the temperature of local heat source on the lower wall of the cavity changes with time as per the sine law,the unsteady natural convection of Cu-water nanofluid in the two-dimensional cavity was studied numerically.The effects of Rayleigh number,nanoparticle volume fraction and cavity height to width ratio on natural convective heat transfer characteristics were investigated on the basis of defined parameters.The results show that the average hourly heat transfer rate of cavity wall increases with the growth of Rayleigh number Ra and the nanoparticle volume fraction,while it decreases and tends to be stable with the increase of cavity height-width ratio D.