微重力池沸腾中的气泡和传热行为数值模拟

基于标准动量传输方程、连续性方程以及能量方程，建立了单个气泡的二维数值模型，考察了微重力过冷核态池内沸腾中的气泡动力学和传热行为.在动量传输方程中耦合了表面张力和Marangoni力，连续性方程和能量方程中耦合了相变效应，考虑了加热面上过热液体层的影响，并引入相场函数捕捉气液界面的动态变化.结果表明:气泡在生长过程中，形状由最初的半球形变为椭球形，最后变为脱附时的梨形；气泡在加热面上自由迁移，呈非轴对称结构，并且气泡上部的温度场呈现为蘑菇云状；气泡的脱附直径正比于g-0.488，脱附周期正比于g-1.113，加热面上的平均热通量正比于g0.229. 

Numerical Simulation of Bubble Dynamics and Heat Transfer during Pool Boiling in Microgravity

A two-dimensional model of the single bubble is performed. The surface tension and Marangoni force are included in the momentum equation. In addition, the continuity equation and energy equation are modified to allow for the phase change. A thin superheated layer is considered in the numerical model. The vapor-liquid interface is captured by the phase field method. The variations of bubble dynamics and heat transfer during subcooling pool boiling in microgravity can be obtained by solving the coupled equations. The results show that the bubble changes from a hemisphere to an ellipsoid and eventually becomes a pear shape. The bubble can randomly move on the surface. Besides, the bubble exhibits non-axisymmetrical shape during growth period. Due to the effect of fluid flow, the temperature field above the bubble appears to be a mushroom shape. The bubble departure diameter and departure time are proportional to g-0.488 and g-1.113 respectively. The average heat flux on the heater surface is proportional to g0.229.