双大涡模拟方法模拟提升管内气固两相流动

Numerical Simulation of Flow Behavior of Gas and Particles in Riser with Large Eddy Simulation Approach

基于Smagorinsky涡黏模型以及颗粒动理学理论,建立了气固两相流双大涡模拟模型。考虑大涡模拟中过滤尺度的影响,给出颗粒相亚格子压力和热传导系数计算模型。考虑颗粒聚团对两相作用的影响,给出了考虑颗粒聚团作用的气固两相多尺度曳力系数模型。数值模拟了提升管内气固两相流动特性,合理地预测出了提升管内气固两相环-核流动结构。模拟结果与Knowlton等实测结果相吻合。

Based on the kinetic theory of granular flow and Smagorinsky eddy viscosity model, a gas-solid two-fluid model by means of large eddy simulation is proposed. The subgrid closures for the solid pressure, viscosity and thermal conductivity are presented. A cluster structure-dependent （CSD） drag coefficient model is proposed to consider the heterogeneity by clusters in the riser. Flow behavior of gas and solids phases is predicted by means of double large eddy simulations. The time-averaged distributions of particles concentration and velocity are obtained, and the core-annular structure is predicted. Simulated results are in agreement with Knowlton et al. experimental data in a riser.