A quantitative study on the influence of cavity distribution on flow and heat transfer characteristics in curved microchannels introducing the cavity throughput ratio

This study presents a comprehensive and quantitative analysis of the impact of cavity distribution on the flow and heat transfer characteristics in curved microchannels. We introduce a new dimensionless parameter, the “cavity throughput ratio (CTR)”, to serve as a universal metric for assessing the effects of cavities on channel flow. The curved microchannel consists of a curved section flanked by two straight sections, with a constant heat flux applied to its bottom surface. Four classic cavity distribution were designed: symmetrical, staggered, exterior-only, and interior-only, with a cavity-free microchannel for comparison baseline. These configurations were evaluated and analyzed based on a range of parameters including Reynolds (Re) number, Nusselt (Nu) number, Poiseuille (Po) number, as well as temperature and velocity contours, vector diagrams, and local pressure and temperature measurements. The results reveal that the staggered cavity distribution reduces the flow resistance most, mutually corroborated with its high CTR. Symmetrical cavity distribution shows the best thermal performance, reaching a maximum thermal performance evaluation criterion (PEC) of 1.65. This study provides valuable practical insights into the optimization of microscale heat transfer devices, shedding light on essential mechanisms for performance optimization.