Measurement of Thin-Film Evaporation Heat Transfer for Evaporators with Sintered Powder Wick Structure

Two-phase heat transfer devices such as heat pipes and vapor chambers are composed of an evaporator, an adiabatic section and a condenser. For the dry-out prevention and capillary purpose, adiabatic sections and evaporators are covered by wick structures. Common wick structures are grooves, mesh, sintered powder and their combination. Combining with the wick structures, the major phase change effects on evaporators are thin-film evaporation. For the research between parameters of wick structure and evaporator performance, we developed a facility to measure the heat transfer on evaporators. To ensure the least heat losing, the path of heat flux and test condition were designed with several thermal guards. A pressure control system was established with balance mechanisms to maintain a stable condition of low pressure. Since temperature differences are very fast while the major phase change effect is thin-film evaporation, a high speed data acquisition system was used. Based on this test platform, the performance of evaporators can be determined at specific conditions.