Analysis of field synergy principle and the relationship between secondary flow and heat transfer in double-layered microchannels with cavities and ribs
Analysis of field synergy principle and the relationship between secondary flow and heat transfer in double-layered microchannels with cavities and ribs
复制标题
DOI：
10.1016/j.ijheatmasstransfer.2016.05.025
复制
发表时间：
2016-10
影响因子：
5.2
通讯作者：
Y. Zhai;Zhouhang Li;Hua Wang;Jianxin Xu
中科院分区：
文献类型：
--
作者：
Y. Zhai;Zhouhang Li;Hua Wang;Jianxin Xu
对含空腔和肋片的双层微通道内的流动与换热特性进行了数值研究。采用二次流强度（Se）和场协同原理对换热性能进行了评价。结果表明，空腔和肋的布置方式对摩擦因数和努塞尔数的影响是明显的。相对的腔和对齐的肋旁边的微通道壁（通道C）表现出最高强度的二次流，从而导致最高的努塞尔数和压降同时。从场协同原理来看，通道C的场协同角β最小，场协同数Fc最大，表明速度场与温度场的协同关系最好。最后，采用热强化因子来评价流动阻力和传热的综合影响。通道C的热增强因子随Se的增加先增大后减小。在本文研究的雷诺数和Re范围内，微通道壁面侧的偏置腔和肋（通道B）的综合效果最好。因此，必须考虑双层微通道的合理几何设计，以达到强化传热和降低压降的目的。
The characteristic of flow and heat transfer in double-layered microchannels with cavities and ribs is investigated numerically. The intensity of secondary flow (Se) and field synergy principle are used to evaluate the heat transfer performance. The results show that the effect of arrangement of cavities and ribs on friction factor and Nusselt number is obviously. The opposite cavities and aligned ribs aside the microchannel wall (Channel C) exhibit the highest intensity of secondary flow, thus resulting in the highest Nusselt number and pressure drop simultaneously. From the view point of field synergy principle, Channel C has the smallest value of field synergy angleβand the highest value of field synergy numberFc, which indicates the best synergy relationship between velocity and temperature fields. Lastly, a thermal enhanced factor is used to evaluate the comprehensive effect of flow friction and heat transfer. The thermal enhanced factor of Channel C increases withSefirstly and then decreases. The offset cavities and ribs aside the microchannel wall (Channel B) shows the best comprehensive effect in the range of Reynolds number andSestudied here. Therefore, Reasonable geometric design of double-layered microchannels must be considered to enhance heat transfer and decrease pressure drop as well.