正弦底面微通道热沉综合性能的数值分析

Numerical analysis of comprehensive performance in microchannel heat sink with sinusoidal bottom wall

为探究正弦底面结构对微通道热沉综合性能的影响,采用数值模拟的方法并结合熵产理论和综合性能评价准则对不同结构的正弦底面微通道进行综合性能评价。结果表明:在所研究的雷诺数Re范围(530—1193)内,正弦底面微通道的熵产增大数Ns,a均小于1,且随正弦振幅的增大(或波长的减小)而减小;当Re较低时,大部分结构的正弦底面微通道的综合性能评价因子η小于1,但当雷诺数Re大于928时均大于1;由于η比Ns,a更有效地反映微通道流动和传热性能的综合关系,因此综合性能评价准则能更准确地评价正弦底面微通道的综合性能。最后,基于模拟结果拟合出努塞尔数比值Nu/Nu 0和摩阻系数比值f/f 0的关联式。

In order to investigate the influence of sinusoidal bottom wall on the comprehensive performance in microchannel heat sink,the performance of microchannel heat sink with different sinusoidal bottom wall was comprehensively assessed using numerical simulation method coupled with entropy generation principle and performance evaluation criteria(PEC).The results show that in the range of studied Reynolds number(Re=530-1193),the augmentation entropy generation number(Ns,a)is less than 1,and decreases with the increase in the amplitude of sinusoidal bottom wall(or the decrease in wavelength).The PEC factors(η)in the most of microchannels with sinusoidal bottom wall are less than 1 at the low Re,but all cases are greater than 1 when Re>928.Becauseηcan reflect the comprehensive relationship between the fluid flow and heat transfer in the microchannel more effectively than N s,a,the PEC can evaluate the comprehensive performance of the microchannel with sinusoidal bottom wall more accurately.Finally,the correlations for Nusselt number ratio(Nu/Nu 0)and friction coefficient ratio(f/f 0)are fitted based on numerical data.