Simulation and experiment of boiling two-phase flow and heat transfer in mini-channels with reticulated pore structure

Abstract

In order to satisfy the operational requirements of electronic devices with small volumes, high heat flow densities, and uniform temperatures, a reticulated pore mini-channel heat sink unit (porosity>72 %) is designed. The mechanism of efficient heat transfer by boiling phase change is studied with deionized water as the cooling medium. A two-phase flow model based on VOF theory is developed, and an experimental platform for testing the boiling two-phase flow and its heat transfer performance in millimeter-scale pore channels is built. The single-phase convective thermal performance and boiling two-phase flow status and heat transfer properties of the heat sink are obtained. The findings indicate that as flow velocity increases, the maximum increase of Nusselt number in two-phase flow can reach 77.2 % in contrast to that in single-phase flow, and maximum reduction in temperature difference across the heated surface can reach 20.1 %. The Nusselt number for the reticulated pore structure is 56.2 % higher than that of a straight mini-channel heat sink, and the heated surface experiences a maximum temperature drop of 3.42 K. Multiple sets of experimental and theoretical results under two-phase flow in pore mini-channels show good consistency. The maximum relative difference in error of the heated surface temperature is only 3.1 %, and the average relative difference in error of the total thermal resistance is 6.68 %. The research will offer significant theoretical and practical contributions to the design of high-efficiency heat sinks with pore mini-channel structure by the boiling phase transition mechanism.