基于MUSIG模型的低温流体过冷沸腾数值模拟

在低温泡状流中,鉴于液相中离散的气泡尺寸大小不一,文中将MUSIG模型应用于低温流体过冷沸腾计算中。通过模拟液氮在竖直圆管内过冷流动沸腾过程,对各尺寸组气泡的分布、轴向空泡份额的分布规律及流动不稳定性进行了分析。计算结果表明:各尺寸组气泡在壁面和中心区呈现不同的分布规律;平均空泡份额沿轴向呈非线性递增变化;由于流型的转变,管内压降将出现突变。

Numerical simulation for subcooled boiling process of low temperature fluid with MUSIG model

In view of the variety of bubble size in low-temperature bubbly flow,a numerical study was performed for subcooled boiling process of liquid nitrogen with MUSIG model.By means of the simulation of subcooled boiling process of liquid nitrogen in vertical round tube,the distribution of the different discrete bubble classes and the average void fraction along the axial direction was systematically analyzed and the flow instability was also studied.The simulation results show that the distribution of the different discrete bubble classes is different on the wall and in the fluid center;the average void fraction along the axial direction increases nonlinearly;the pressure drop changes sharply in the tube due to the transition of the flow patterns.