气泡从浸没孔中生成与上升的数值模拟

应用改进的Level Set方法和Navier-Stokes方程，结合ALE数值算法，三维模拟了常流量下气泡在静止黏性液体中从浸没孔中生成与上升的过程。考察了气泡在两种不同的黏性液体以及在单孔和多孔条件下的生长过程。模拟结果与实验观测定性相符。数值试验表明，改进的Level Set方法改善了气泡的容积守恒性。模拟结果显示，在不同的黏性液体中单孔气泡的生成行为很不相同，在Paratherm传热流体中生成的气泡直线上升，而在水中则是盘旋上升；多孔气泡的生成不同步，气泡的尺寸及空间分布极其不均匀。

Numerical simulation of bubble formation and rise from submerged orifices in viscous liquid

An improved level set method coupled with the Navier-Stokes equation,and ALE(Arbitrary Lagrangian Eulerian) algorithm are incorporated to simulate the 3-D bubble formation and rise through orifice immersed in a quiescent viscous liquid under constant gas flow condition.The simulation results on the bubble behavior are qualitatively in good agreement with experimental observations in the literature.The numerical examination shows that the volume conservation is significantly improved with the improved Level Set method.The simulated results indicate that the behavior of bubble formation from single orifice is observably different in two different viscous liquids.The bubble rises rectilinearly in the Paratherm heat-transfer fluid while rising in a zigzag path in water.The bubble formation is nonsynchronous at multiple orifices.And the bubble sizes and bubble distribution are not uniform in a multi-orifice system because bubbles coalesce and break up more frequently due to bubble and bubble wake interaction.