Simulation of single-phase and subcooled flow boiling in manifold microchannel heat sinks with micro-pin-fin wall

Abstract

Subcooled flow boiling in manifold microchannel (MMC) heat sinks holds significant potential for high-flux thermal management in microelectronics. However, further investigation into novel micro-pin-fin wall is necessary to dissipate heat flux more effectively. In this paper, MMC heat sinks with one row, staggered two rows, and three rows micro-pin-fin wall were designed based on conventional rectangular manifold microchannel (RMMC), identified as PMMC1, PMMC2, and PMMC3, respectively. Numerical simulations of these MMC heat sinks were performed under single-phase and two-phase conditions using chtMultiRegionSimpleFoam and a custom solver that couples subcooled flow boiling in fluid with conjugate heat transfer in solid. The results indicate that in single-phase flow, PMMCs can achieve higher heat transfer efficiency with lower pressure drop than RMMC. PMMC3 reduces the average chip temperature by up to approximately 9 K and decreases the pressure drop by as much as 23.3 %. In subcooled flow boiling, PMMC2 demonstrates the best cooling performance, reducing the chip temperature by up to 9 K. In contrast, at low mass flux, the heat transfer performance of PMMC3 is nearly equivalent to that of RMMC due to blockage of the channels by excessive bubbles. All configurations have excellent temperature uniformity under various conditions, with the maximum temperature difference not exceeding 3 K. The presence of micro-pin-fins in PMMCs increases the number of nucleation sites, advancing the onset of nucleate boiling (ONB), particularly in PMMC3. These findings not only provide scientific guidance for the structural optimization and performance enhancement of MMC heat sinks but also offer a feasible path for engineering applications in the field of thermal management.