Development of three-dimensional vortex method for gas-liquid two-phase flow around an obstacle and verification by experiment

1.自由湍流三维涡旋法的发展本文提出了一种求解单相射流的三维涡旋法。模拟了圆形喷嘴向同一方向共流的复合射流。采用面板法求解喷嘴内流动问题。利用拉格朗日方法模拟了喷嘴边缘涡元的释放过程。涡单元采用blob模型。发现各涡单元涡度分布函数和计算域轴向长度对数值结果有影响。含气泡射流三维涡旋方法的发展应用三维涡旋方法对含小气泡射流进行了数值模拟。仿真研究了喷嘴出口处扰动的影响。测量垂直向上气泡流中障碍物的静压测量垂直向上气泡流中障碍物的静压。含气泡自由湍流涡旋法的发展研究了含气泡自由湍流涡旋法。该方法可以考虑两个阶段之间的相互作用。该方法将液体涡度场离散为涡单元。用拉格朗日方法计算了涡单元的行为和气泡的运动。利用涡室法估计了气泡引起的涡量变化。通过对载有气泡的平面混合层的数值模拟，验证了该方法的有效性。

1.Development of three-dimensional vortex method for free turbulent flowA three-dimensional vortex method for single-phase jet is developed. A compound jet issuing from a round nozzle into the stream co-flowing in the same direction is simulated. The flow in the nozzle is solved by a panel method. The vortex elements are released from the nozzle edge, and the behavior is simulated by the Lagrangian approach. A blob model is employed for the vortex element. The distribution function for the vorticity in each vortex element and the axial length of the computational domain are found to affect the numerical results.2.Development of three-dimensional vortex method for jet entrained with bubbleThe three-dimensional vortex method is applied to simulate the jet loaded with small bubbles. The simulation examined the effect of the disturbance at the nozzle exit.3.Measurement of static pressure on an obstacle installed in vertically upward bubbly flowThe static pressures on an obstacle installed in vertically upward bubbly flow are measured.4.Development of vortex method for bubble-laden free turbulent flowA vortex method for bubbly flow is developed. The method can consider the interaction between the two phases. In the method, the liquid vorticity field is discretized into the vortex elements. The behavior of the vortex element and the motion of the bubble are calculated by the Lagrangian method. The change of the vorticity due to the bubble is estimated by the vortex in cell method. The validity of the method is confirmed by applying the simulation of a plane mixing layer loaded with air bubbles.