Gradient distribution surface texture for enhancing the surface heat transfer performance of the mini-channel

In the fields of aerospace, microelectronics and automotive, the mini-channel requires the working surfaces with very high heat transfer coefficients to meet extreme heat transfer requirements. In recent years, preparing microstructures on the sample surface has become an emerging method for improving the surface heat transfer performance. However, most studies have focused on the uniform surface microtextures, which cannot maximize the heat transfer performance of the surface. The goal of this study is to improve the heat transfer performance of mini-channel surfaces. Firstly, based on the theories of heat conduction and fluid flow, a thermal-flow coupling model of the mini-channels with surface microtextures is established. Secondly, on the basis of the coupled model, the influences of the position, type, size and distribution of microtextures on the heat transfer performance of the mini channel surface are simulated and analyzed. Subsequently, according to the fluid flow and interface heat transfer behavior within the mini-channel, a gradient-distributed surface microtexture is proposed to further improve the heat transfer performance of the mini-channel. Finally, the confirmatory experiments demonstrate that the established thermal-flow coupling model has high accuracy, and the proposed gradient distribution surface texture can significantly improve the heat transfer performance in mini-channels. Compared to the mini-channels with the uniformly distributed surface microstructures, the comprehensive heat transfer evaluation coefficients in mini-channels are increased by 36.5 %. This study can provide a theoretical basis for the preparation of fluid enhanced heat dissipation surfaces in mini-channels.