负压下热管管外降膜蒸发的换热特性研究

Study on heat transfer of falling film evaporation characteristic on heat pipe in the negative pressure

热管作为一种高效的传热方式,以其优良的传热性能在工业生产的不同领域中得到了广泛应用。根据流体边界层理论,研究了负压下热管管外降膜蒸发过程中速度边界层和热边界层的形成规律,给出了速度边界层和热边界层厚度的计算函数。在此基础上得到了该模型下热管管外降膜蒸发换热系数的计算方法,推导出相关的计算公式。分析了真空度、喷淋负荷以及传热温差等对热管管外降膜蒸发传热性能的影响,为热管在负压下管外降膜蒸发的工程应用和研究提供了指导。

As a high performance heat transfer method,heat pipe is widely used in different field of industry manufacture. Based on the boundary layer theory in the article ,the rules of the velocity and the thermal boundary layers outsides of the heat pipe fallingfilm evaporation in the negative pressure are discussed,and the formulas of thickness of both velocity and thermal boundary layers are given. Then based on these formulas ,the calculation method of the falling film evaporation heat transfer coefficient outsides of the heat pipe is discussed. The effects of vacuum,the falling liquid load,temperature gradation and etc. to the evaporation heat transfer performance were analyzed, h would provide the guidance in engineering application of the evaporation outsides of the heat pipe in negative pressure.