循环流速对环管反应器内液-固二相流动影响的CFD模拟

Abstract

以聚丙烯工艺中的环管反应器(包括环管与轴流泵)为研究对象,首先通过CAd软件绘出该反应器的三维模型,然后在gAMbIT软件中划分该系统的网格。在此基础上,建立了环管反应器内液-固两相的“颗粒动力学-欧拉双流体“模型。其中,采用颗粒动力学描述固相(颗粒相)黏度与压力,采用多重坐标系模型描述轴流泵。采用上述模型模拟了循环流速对环管反应器内液-固两相流动行为的影响。结果表明,高循环流速有助于颗粒在环管“直管“部分均匀分布,但将造成颗粒在环管“弯管“部分不均匀分布。

In the present study,the fluid dynamics of a liquid-solid polypropylene loop reactor composing of loop and axial flow pump was simulated.Firstly,the three-dimensional physical model was used to describe the loop reactor by using the CAD software,its mesh was obtained in Gambit.Furthermore,a particle kinetics-Euler two-fluid model was established,in which the particle kinetics was used to describe the viscosity and pressure of the solid phase,a multiple reference frame model(MRF) was used to describe the axial flow pump.Accordingly,the model was used to study the effect of the circular flow rate on the fluid dynamics of the liquid-solid loop reactor.The results showed that the high circular flow rate was favorable for the particle in the linear part of loop reactor to had the symmetrical distribution and for the particles in the curving part of loop reactor to had asymmetrical distribution.