平板热管内气液两相流动与传热的可视化实验研究

Visualization Study of Vapor-liquid Two Phase Flow and Heat Transfer in Flat Plate Heat Pipe

本文基于高速摄像仪设计搭建了平板热管气液两相流动与传热的可视化平台,开展平板热管受限空间内气液两相工质运行状态和相变传热行为的可视化观测。研究结果表明,平板热管存在突然启动和渐进式启动两种启动方式,在高充液率情况发生突然启动,而在低充液率情况下发生渐进式启动。在准稳定运行阶段,蒸发面先处于能量积累状态,随后热量伴随着核态沸腾快速释放到冷凝面,热管蒸发段和冷凝段壁面温度表现出周期性的温度脉动变化。在热量积累过程中平板热管蒸发段与冷凝端之间的传热性能弱,在核态过程中蒸发段与冷凝端之间的传热性能强。

The vapor-liquid two phase flow and heat transfer in flat plate heat pipe is experimentally investigated by the use of a visualization system.The vapor-liquid two-phase hydrodynamics and phase-change heat transfer behaviors in the small confined space is observed.The results indicate that there exits two start-up types for the flat plate heat pipe,i.e.the sudden start-up type for the high water filling ratio and the gradual start-up type for the low water filling ratio.For quasi-steady state,the amount of energy is initially accumulated at the evaporation section,and then the energy is quickly transferred to the condensation surface during the nucleate boiling process.Evident temperature oscillations are observed on both the evaporation surface and condensation surface.During the energy accumulating process,the heat transfer between the evaporation surface and condensation surface is weak,however,the thermal performance during the nucleate boiling process is superior.