Abstract: Heat pipe is high performance heat transfer equipment，in order to reduce its complexity in the process of theoretical research，it is necessary to make some simplification.Aiming at the applicability of some basic hypothesis，a one-dimension evaporation-condensation model is proposed.Through primary integration，the governing equations are simplified and the numeric result is got，which indicates that there exist obvious boundary layers in the temperature，velocity and pressure fields in the evaporation and condensation phase interface，and it is more obvious in the evaporation phase interface，where the velocity and pressure have large gradient.When Reynolds number is large enough，the gradient of temperature is large too.From boundary layer phenomenon，a deduction is derived，thermal short-circuit effect，which means the ultimate state of the vapor will be such that the temperature is uniform，the vapor is saturated，and its thermal resistance is zero.

Key words: heat pipe, evaporation-condensation, boundary layer, thermal short-circuit, phase line

摘要： 热管是一种高效传热元件，为了降低理论研究的复杂性，对其做出简化是必要的。针对一些基本假设的适用性，本文建立了一维蒸发-凝结流动传热模型。通过初积分，对控制方程进行了化简和数值计算。结果表明，温度、流速以及压力场，在蒸发和凝结相界面上明显存在着边界层，其中蒸发侧尤为明显，速度、压力梯度较大；在雷诺数很大的情况下，温度梯度也较大。由边界层现象推出了蒸发-凝结流动传热的热短路效应：汽相工质的最终趋势是达到均匀的温度场和饱和状态，汽相热阻为零。

关键词: 热管, 蒸发-凝结, 边界层, 热短路效应, 相线