直方槽道中重力对颗粒相二次流的影响

采用Eulerian／Lagrangian方法模拟直方槽道中气粒两相流动过程。气相采用大涡模拟方法,直接求解大尺度涡运动,小尺度涡采用标准的Smagorinsky亚格子模式模拟,壁面采用幂次率应力模型代替无滑移边界条件。颗粒相采用轨道模型求解。大涡模拟预报的气相平均速度与DNS结果相吻合。结果表明,在直方槽道流向截面,气相存在二次流现象。受气相二次流的作用,颗粒相也存在类似于气相的二次流现象,并考察了重力对颗粒相二次流的影响。

Influence of gravity on secondary flow of particle phase in a square duct

Gas-particle flow in a square duct was studied by using Eulerian/Lagrangian approach. The large eddy simulation was used to simulate the turbulence of gas phase, where the motion of the large scale structures were solved directly and the effects of the unresolved scales were modeled by the standard Smagorinsky sub-grid-scale model. The no slip boundary condition on the surface of walls is substituted by the wall-shear stress model. Particles were tracked in Lagrange trajectory way. Predicted statistical averaged velocity of gas by LES agreed well with the present DNS date. The secondary flow pattern of gas phase in the cross section of the square duct was predicted. Predicted results show that there is also a secondary flow pattern for particle phase due to the secondary flow of gas phase. Influence of gravity on secondary flow of particle phase was investigated.