Numerical simulation of flow and heat transfer performance in branch and combined-branch microchannel

Abstract

The pressure drop at the inlet and outlet of rectangular microchannel is large, and the temperature distribution is uneven; Fractal microchannel is limited by fractal dimension and the number of branches, so its application scope is narrow. A branch and combined-branch microchannel heat sink was designed by combining the advantages of rectangular microchannel and fractal microchannel, and Fluent software was used to numerically simulate its heat dissipation process to study the flow and heat transfer performance when the branch tilt angle inside the microchannel changes. The results show that at the heat flow of 100 W/cm2, when the Re is 970 and the branch tilt angle is 90°, the average temperature of the branch and combined-branch microchannel decreases by 11.9 K, the maximum temperature decreases by 14.2 K, the Nu increases by 85.7%, and the performance evaluation criterion (PEC) is also the best by reaching 1.44. The introduction of branches can increase the heat transfer area inside the microchannel, form a new boundary layer, and generate vortices at the inner side of the branch, effectively improving the heat transfer performance of the microchannel heat sinks, which provides new theoretical basis for optimizing the design of microchannels.

Keywords

• heat transfer; microchannel; micro device; numerical simulation; heat transfer