燕尾形轴向微槽热管的流动和传热特性

摘要

建立了燕尾形轴向微槽热管传热和液体流动模型并进行了数值求解,计算了其最大传热能力.模型考虑了气液界面剪切力的作用,分析了热管内气、液相流体压力和流速及弯月面毛细半径沿轴向的变化特性,并讨论了热负荷对蒸发段端口毛细半径的影响,以及工作温度和吸液芯结构对最大传热能力的影响.研究表明:弯月面毛细半径沿轴向非线性增加,在蒸发段和绝热段变化较小,而从冷凝段开始急剧上升;热管内蒸气沿程压差远小于液相压差;液体的平均速度远小于蒸气的平均速度;沟槽热管的最大传热能力受工作温度和毛细芯结构尺寸的影响较大;燕尾形底宽的增大或微槽高度的增加有利于提高热管的最大传热能力,而蒸气腔半径对最大传热能力的影响不明显.同时,还通过实验验证了本模型的正确性.%A theoretical model for flowing and heat transfer in a heat pipe with axially swallow-tailed microgrooves are devel-oped and calculated numerically to propose the maximum heat transport capability. In the model, the effect of the liquid-vapor in-tertacial shear stress is included. The axially variation of pressure and velocity both in the liquid phase and vapor phase is ana-lyzed. And the effect of the heat load on the meniscus radius at the end cap of evaporation section is discussed as well as the effect of working temperature and cross section structure of the wick on the maximum heat transfer capability. It is indicated thai the me-nilus radius increases non-linearly ,along the axial direction. At the evaporator and adiabatic section, it will increase slowly, while it begies to increase drastically at the beginning of the condenser section. The pressure difference in the vapor phase along the axi-ally direction is much smaller than what in the liquid phase, however, the average velocity of the liquid is much larger than what of the vapor. In addition, it is confirmed the maximum heat transport capability is deeply affected by the working temperature and the size of the wick. A groove wick structure with a wider bottom width or higher grtx,ve height will enhance the heat transfer capa-bility, while the influence of vapor core size is less obvious. And the accuracy of the model is also verified by the experiment.