毛细相变流体回路冷凝界面的稳定性

Stability of the Condensing Interface in a Capillary Loop with Phase Change

依据毛细管内冷凝液柱的卢卡斯-沃什伯恩(Lucas-Washburn)方程,获得了相变毛细管中流体上升高度与毛细管半径以及热流密度的关系式,并将此关系式推广到毛细相变流体回路中,利用小扰动理论通过对界面高度的变化来分析研究冷凝界面的稳定性。文章通过研究三种不同运行状态下的界面动力学行为发现,在实际运行过程中,蒸汽管路的压力波动将使冷凝界面形成具有一定振幅的波动。

A mathematical model based on the Lucas-Washburn equation was developed to address the relations of the capillary height, capillary radius and the heat flux in a capillary column and the equation was extended to a capillary loop for investigating the stability of the condensing interface with phase change by some simplifications. The stability of the condensing interface was studied by introducing a small disturbance into capillary height. The dynamics performances of the condensing interface under three different operating conditions were discussed. The results show that there is avibration with a certain amplitude on the condensing interface due to the periodic oscillation of the pressure in the system.