旋转式气液混合器流场数值模拟与状态分析

Numerical Simulation and Status Analysis of the Flow Field in a Rotary Gas-Iquid Mixer

为提高不同工况下旋转式气液混合器轴承支承承载力,采用Fluent流体分析软件,对静止与转动工况下混合器内部的气液两相流体进行了流场湍流数值模拟.采用流体体积模型与压力隐式算子分割算法,进行了气液两相混合流体的瞬态流动追踪,分析了相应的流场分布状态.结果表明:静止状态下,混合流体的分层主要受入口流速的影响,流速越大,分层区距离入口越远,各相明显分层,流型由规则的层状流逐渐过渡为波状流,且波形逐渐变大;转动状态下,流场分布主要受离心力作用的影响,入口流速一定时,随着转速的提高,流型由重力方向的分层流逐渐转化为螺旋轴状流,液相贴近壁面,气相靠近回转轴线,圆周方向上呈环状分层.

In order to improve the bearing capacity of the rotary gas-liquid mixer under different conditions,the gas-liquid two-phase fluid flow in the mixer under static and rotating conditions was numerically simulated, using Fluent fluid analysis software. By using the fluid volume model and the pressure implicit with splitting of operators, the transient flow tracing of the gas-liquid two-phrase mixture was carried out, and the corresponding flow field distribution was analyzed. The results show. In the stationary state, fluid mixing layer is mainly affected by the influence of inlet velocity ;The large the velocity is, the remoter is the delamination area from the entrance, and more evident is the stratification; Flow pattern transites from the stratified flow to wavy flow gradually,and the waveform becomes large. In the rotating state, flow field distribution is mainly affected by the action of centrifugal force;While inlet velocity is given, with the increase of rotational speed, flow pattern stratified by the direction of gravity flow is transformed to spiral shaped flow gradually;The liquid phase is close to the wall, and the gas phase is around the axis of rotation,with annular lamination in circumferential direction.