Enhanced thermal performance by spatial chaotic mixing in a saw-like microchannel

Abstract

Convection heat transfer in microchannel is an alternative cooling technique for electronic devices. But the long-lasting dominant laminar flow seriously inhibits the further enhancement of single-phase convection. In this work, a saw-like microchannel configuration is proposed to improve convective heat transfer by substantially enhancing spatial fluid mixing and significantly interrupting boundary layer. The heat transfer and hydraulic performance of this configuration are numerically investigated in opposite directions. The diodic performance is also studied by comparing the pressure drop and Nusselt number (Nu) in the forward and backward directions. Parametric study is conducted to investigate the roles of channel width and bifurcation angle on fluid flow and convection. Finally, convective heat transfer in both directions is significantly enhanced in this saw-like microchannel owing to the intensified spatial fluid mixing. Another enhanced factor is the periodic interruption of thermal and fluid boundary layers. Compared to conventional rectangular microchannel configuration, the Nu is dramatically enhanced by about 2.5-fold at Re = 440. The thermal diodicity (Dit) and pressure drop diodicity (Dip) are up to 1.4 and 2.1 at Re = 440, respectively. A comprehensive comparison is presented to show the advantages of our design.