高温锂热管三相耦合数值模拟

Numerical Simulation of Three-Phase Coupling for High-Temperature Lithium Heat Pipe

为了研究锂热管的传热机理,推动锂热管在小堆中的应用。采用COMSOL Multiphysics软件,建立了管壁、吸液芯和管内蒸气腔室的固液气三相耦合模型,对热管的温度分布、压力分布和速度分布进行计算。结果表明:当蒸发段的热流从13.9 kW增加到20.8 kW时,管壁温度、蒸气温度、蒸气压力以及吸液芯内部的液体压力、液体轴向速度随着加热功率的增加而增加,蒸气轴向速度随着加热功率的增加先增加后降低。在稳态运行时,管壁温度呈现阶梯形下降,而蒸气温度和压力基本保持不变,表明了锂热管具有良好的等温性。

To study the heat transfer mechanism of lithium heat pipes and to improve their application in small reactors,a solid-liquid-gas three-phase coupled model of the tube wall,the wick and the vapor chamber inside the tube is developed using COMSOL Multiphysics software.The results show that when the heat flow in the evaporation section increases from 13.9 kW to 20.8 kW,the pipe wall temperature,steam temperature,steam pressure,liquid pressure inside the wick,and liquid axial velocity increase with the increase of heating power,while the steam axial velocity first increases and then decreases with the increase of heating power.In the steady-state operation,the pipe wall temperature decreases step by step,while the vapor temperature and pressure remain basically unchanged,indicating that the lithium heat pipe has good isothermality.