Study on heat transfer enhancement of spray cooling with bionic vein channel structured surface

Abstract

Inspired by the fluid transportation capabilities of leaf vein structures in nature, a novel approach is proposed to enhance spray cooling heat transfer performance through improving liquid film distribution. In this study, a leaf vein channel structure was laser etched onto a heat exchange surface and a non-contact open spray cooling test platform based on the principle of induction hea ting was established. The spray cooling heat transfer performance of the enhanced surfaces with identical leaf vein channel shapes but varying channel depths was investigated under different flow rates. The results indicate that, across all tested flow rate conditions, the spray cooling heat transfer performance of the leaf vein channel surpasses that of the smooth surface. Notably, within the two-phase region, an observed 50 % increase in heat flux density highlights significant enhancement effects provided by the leaf vein channels. Furthermore, research findings suggest that for leaf vein channel depths <0.5 mm, greater depth corresponds to improved enhanced heat transfer effects during spray cooling processes. Utilizing high-speed camera technology throughout our investigation allowed us to capture distinct liquid motion phenom ena known as “liquid columns” occurring at the center of each leaf vein channel. These liquid columns exhibit changes in shape and motion mode corresponding to variations in surface temperature.