幂律流体在正弦粗糙微通道的流动和传热特性

Characteristics of Flow and Heat Transfer for Power-Law Fluid in Microchannel with Sinusoidal Surface Roughness

基于Poisson-Boltzmann方程、修正的Cauchy动量方程和能量方程,对双电层作用下幂律流体在正弦粗糙微通道中的流动和传热问题,建立模型控制方程组,并且使用高精度紧致差分格式进行数值模拟。然后,计算了不同幂律指数和粗糙度下的速度和温度。进一步研究了幂律指数和粗糙度对通道阻力系数、平均Nusselt数和能效比的影响。结果表明:幂律指数越小,流动阻力越小且能效比越高;增加粗糙度,流动阻力上升且传热性能增强,可在一定范围内提高能效比。

The governing equations are established by the Poisson-Boltzmann equation,modified Cauchy momentum equation and energy equation.The flow and heat transfer of power-law fluids in rough microchannels are calculated by the high accurate numerical algorithm.Then,the velocity and temperature of different power-law index and roughness are obtained by the simulation.Furthermore,the effects of power-law index and roughness on flow friction factor,average Nusselt number and energy efficiency ratio are investigated.The results show that the flow friction factor decreases and the energy efficiency ratio increases with the decrease of the power-law index.The resistance and the heat transfer in microchannels increase with the increase of the roughness.The energy efficiency ratio increases with the increase of the roughness within limits.