气泡在内置交错矩形肋管道中自由上升的FTM直接数值模拟

采用直接数值模拟的FTM（Front-Tracking Method）方法研究在重力作用下单气泡在竖直内置矩形肋管内的自由上升.选择矩形肋的肋高、肋距与方管宽度的比值作为管道几何特征值，用莫顿数作为流体特征参数，分析不同肋高、肋距及莫顿数情况下的气泡自由上升，研究不同几何特征及流体参数对气泡运动轨迹的影响.研究表明：在矩形肋片的影响下气泡上升时形状不对称，存在水平方向位移，表现为"蛇形"上升.这种现象与管道几何结构及气泡周围流体性质有关，肋高越大，现象越明显；气泡周围流体的粘度越小，水平方向位移越大.

Numerical Simulation of Free-Rising of Bubbles in a Tube with Fins Using Front Tracking Method

Direct numerical simulation of FTM (Front Tracking Method) was used to study free rising motion of single bubble in a tube with fins in gravity. Ratio of fin height and pitch to tube length of a side are chosen as geometric characteristics. Morton number is used as characteristic parameter of fluid. With analysis on free rising motion of bubbles at different fin height, pitch and Morton number effects of geometric characteristics of tube and parameters of fluid on motion trajectory of bubbles are studied. It shows that under effect of fins bubble shape is asymmetry and bubbles have lateral displacement like a "snake".This phenomenon is associated with geometric structure of fin and fluid around bubble. The higher fin height is, the more obvious phenomenon becomes. The smaller the viscosity of fluid around bubble is, the greater the horizontal displacement is.