回路振荡热管稳定运行条件及循环特性的热力学分析

Thermodynamics analysis of steady state circulation flow conditions for a loop oscillating heat pipe

以简单回路振荡热管为热力系统,通过热力学分析,导出了稳定循环的条件:蒸发端吸热量等于冷凝端放热量,且必须考虑耗散功的影响作用。推导出稳定循环过程的特征和热力学参量变化的规律,揭示了过程能量转换的特点。结果表明:吸(放)热过程包括潜热和显热,汽相比体积随压力的变化因素不可忽视;蒸汽干度和密度的变化与温度、压力同向,与流速相反;此过程中的能量转换是维持能量传递的重要条件。

The characteristics of steady state circulation flow in a single loop oscillating heat pipe have been analyzed from a thermo-mechanical viewpoint. The results show that the heat absorption from the evaporator section must be equal to the heat release from the condenser section and that dissipation work is necessary to maintain stable running. The laws governing the changes in thermodynamics parameters and characteristics of the energy conversion processes involved are derived. It is shown that absorption or discharge of heat, including latent heat and sensible heat, as well as changes of vapor volume ratio with pressure must all be considered. The variation in both dryness fraction of the steam and its density follows that of temperature and pressure, whereas the variation in flow velocity is in the opposite sense. Furthermore, energy conversion is a necessary condition to maintain energy transfer during the circulation.