基于幂律液固曳力模型流化床内湿颗粒流动特性的研究  

Investigation on flow characteristics of wet particles with power-law liquid solid drag models in fluidized bed

作　　者：袁子涵 王淑彦[1] 邵宝力[1] 谢磊 陈曦[1] 马一玫[1] YUAN Zihan;WANG Shuyan;SHAO Baoli;XIE Lei;CHEN Xi;MA Yimei(School of Petroleum Engineering,Northeast Petroleum University,Daqing 163318,Heilongjiang,China)

机构地区：[1]东北石油大学石油工程学院,黑龙江大庆163318

出　　处：《化工学报》2023年第5期2000-2012,共13页CIESC Journal

基　　金：国家自然科学基金项目(51876032);黑龙江省自然科学基金项目(ZD2019E002)。

摘　　要：采用欧拉-欧拉双流体模型(TFM)结合颗粒动理学理论(KTGF)方法,对三维幂律流化床中的液固两相流动行为进行了模拟。基于幂律流体的流变方程以及压降方程,提出了两种幂律液固曳力模型,引入了考虑液膜效应的湿颗粒动态恢复系数模型,计算幂律流体与湿颗粒之间的作用力。将预测固含率分别与文献中测得的实验数据进行比较,结果表明结合动态恢复系数模型的相对误差介于0.45%~1.59%,与实验结果吻合较好。探究了稠度系数K以及流性指数n对颗粒流动特性的影响,结果表明随着流变参数的增大,床层内的颗粒平均浓度降低,湿颗粒表面液膜逐渐变厚,法向恢复系数降低;颗粒拟温度随n的升高先增大后减小,随K的上升而增大;曳力系数、颗粒压力以及颗粒黏度均随流变参数的增大而逐渐减小。颗粒在壁面处的浓度明显高于中心处附近的浓度,且颗粒在中心处向上运动,在壁面处附近回落,在流化床中形成环-核结构。The liquid-solid two-phase flow behaviors in the power-law fluidized bed are simulated using the Euler-Euler two-fluid model(TFM)based on the kinetic theory of granular flow(KTGF).Based on the pressure drop equations and rheological equations of power-law fluids,two kinds of power-law liquid-solid drag models are presented.And the dynamic restitution coefficient model of wet particles considering the liquid film effect is introduced to calculate the interaction between power-law fluids and particles.The predicted solid holdups are compared with the experimental values in references,the results show that the relative errors of power-law liquid-solid drag models combining dynamic restitution coefficient model are between 0.45%and 1.59%,which is closer to the experimental results.The influences of the consistency coefficients and the flow behavior indexes on the flow characteristics of the particles are explored,indicating that with the increase of the rheological parameters,the averaged solids holdup in the fluidized bed decreases,and the liquid film covered on the surface of wet particles becomes thicker and the normal restitution coefficient decreases.The granular temperature increases first and then decreases with the increase of flow behavior index,and rises with the increase of consistency coefficient.The drag coefficient,granular pressure,and granular viscosity all gradually decrease as the rheological parameters enhance.The concentration of particles near the wall is obviously higher than that near the center,and the particles move upward at the center and fall in the vicinity of the wall,forming the classic core-annulus structure.

关 键 词：幂律液固曳力模型 动态恢复系数模型 流化床 液膜厚度 两相流 数值模拟 

分 类 号：TQ018[化学工程]