应用CFD-DEM耦合模拟计算排泥管及法兰连接处固液两相流（英文）

Num erical simulation for solid-liquid two-phase flow in discharge pipeline and flange connection by CFD-DEM coupling

对于管内固液两相流数值模拟,一般的做法是将固体颗粒相视为拟流体,采用多相流的CFD方法计算,这难以体现固体颗粒形状大小、碰撞、凝聚和分离等特性。选取常规的两段管径为0.7 m水平排泥管道和一个连接法兰段作为研究对象,运用CFD软件ANSYS-FLUENT模块与离散元软件EDEM耦合求解排泥管内及法兰连接处固液两相流。计算的来流速度为5.0 m/s,固体颗粒密度为1 300~2 300 kg/m^3,固体颗粒入口体积率为10%~30%,粒径在20~60 mm范围内随机变化。因加工和安装的问题导致在管道法兰连接处存在凸出或凹进不平顺的情况。计算得到了在不同的法兰连接状况下的固液两相流场、固体颗粒轨迹和固相体积率分布等结果。

For the numerical simulation of solid-liquid two-phase flow in pipe,the conventional CFD approach is using multiphase flow and treating solid particles as a kind of quasi-fluid,but it is hard to describe the characteristics of solid particles such as shape and size,collision,agglomeration and separation. In this paper,therefore,one flange connection and two conventional horizontal pipes with 0. 7 m in diameter were selected as research objects. Discrete element software EDEM was coupled with CFD software FLUENT to simulate the solid-liquid twophase flows and the distribution of particle concentration in the pipes and flange connection. The inlet flow speed was 5. 0 m/s. The solid particle density ranged from 1 300 kg/m3 to 2 300 kg/m3. The solid volume rate at pipe inlet was 10% - 30% and the diameter ranged from 20 mm to 60 mm. As the results of the simulation,the solidliquid two-phase flows,the trajectories of the solid particle cluster and solid volume rate distributions were obtained in different flange connections due to manufacture and improper installation in practical application.