微气泡减阻的数值模拟方法及尺寸效应

分别采用混合物模型、欧拉双流体模型和相群平衡模型对底部通气的二维平板微气泡减阻效果进行了模拟分析,探讨了气泡直径、喷气速度对微气泡减阻率的影响,并对其尺度效应进行研究.结果表明:减小气泡直径可以增加微气泡减阻率;在一定的范围内,减阻率随着喷气速度的增加而增大,但喷气速度过小或过大都将影响减阻效果;相群平衡模型比其他2种模型的数值模拟结果更接近于试验结果;由于物体尺寸增加所致的雷诺数增大在一定程度上会降低微气泡减阻率.

Numerical Simulation Methods of Micro Bubbles Drag Reduction and Scale Effect

Abstract： Based on the mixture model, Euler two fluid model and population balance model, bubble drag reduction using gas injection for the flow over a two dimension flat plate was numerically simulated. Effects of bubble size and gas injection rate on bubble drag reduction and the scale effect were analyzed. The results show that the decrease of bubble size can increase drag reduction which increases along with the increase of gas injection rates within a certain range. When the gas injection rate is too low or too high, drag reduction would decrease. The results obtained by using the population balance model are closer to the experimental data than those obtained by using other models. If Reynolds number increases due to the increase of the plate size, the drag reduction level would decrease.