基于IS–FEM的颗粒曳力系数计算与试验验证

PARTICLE DRAG COEFFICIENT CALCULATION BASED ON IS-FEM AND EXPERIMENTAL VERIFICATION

基于浸没光滑有限元模型(immersed smooth finite element model,IS-FEM),计算球形与非球形颗粒曳力系数。设计颗粒曳力图像测量试验,验证IS-FEM模拟精度。颗粒相的运动行为基于连续介质理论的光滑有限元法求解;流体控制方程通过特征分解的半隐式有限元法求解;颗粒与流体相通过非贴体网格交换数据。结果表明,球形颗粒流场特征对称分布,非球形颗粒稳定沉降时长轴与重力方向垂直。不同雷诺数下球形颗粒的曳力系数计算值与Stokes曳力系数一致,非球形颗粒曳力系数高于等效球形颗粒,IS-FEM计算值与沉降试验吻合良好。

The drag coefficients of spherical and non-spherical particles are calculated based on the immersed smooth finite element model(IS-FEM). A particle drag image measurement experiment is designed to verify the numerical simulation result. The motion of particle is solved by smooth finite element method with continuum theory. The fluid governing equation is solved by semi-implicit characteristic-based split method. Data exchange between particle and fluid phase is carried out in non-fit mesh. The results show that the velocity field around spherical particles are symmetrically distributed, and the long axis of the non-spherical particles is perpendicular to the gravity direction when the particles are in a stable settlement. The calculated drag coefficients of spherical particles are consistent with the Stokes theory under different Reynolds numbers, and the drag coefficient of non-spherical particles is higher than that of equivalent spherical particles. The predicted value of IS-FEM is in good agreement with the experimental measurement.