流化床内稠密气固两相流的数值模拟

Numerical Simulation of Dense Gas-solid Two Phase Flows in Fluidized Beds

采用FLUENT软件对流化床内稠密气固两相流进行模拟,研究炉体结构和入口气体速度对沉积炉内气固两相流动状态的影响.结果表明,在锥角为60°的沉积炉内形成的散式流化床具有"环-核"结构,且相对于平底结构沉积炉具有较长的气体滞留时间,有利于制备结构均匀,质量优良的热解炭涂层材料.入口气体速度不宜过大或过小,过小的入口气体速度导致沉积炉内颗粒速度分布混乱,无法形成"环-核"结构,过大的入口气体速度导致沉积炉内颗粒出现返混现象.此外,当入口气体速度增加时,沉积炉内中心区域的气相和颗粒平均速度都逐渐增加,而对气相速度的影响较为明显,对颗粒速度的影响相对较小.

To investigate the effect of the furnace structure and inlet gas velocity on the flow behavior of gas and particles in fluidized beds,numerical simulation of dense gas-solid two phase flows in fluidized beds was simulated using FLUENT software.The results show that the dispersion fluidized bed formed in depositing furnace with 60°cone angle has core-annulus flow structure and longer gas residence time,which is beneficial to prepare the Si-LTIC coating with uniform structure and excellent quality.Inlet gas velocity should be moderate,the slow inlet gas velocity leads to the chaos of the particle velocity distribution,which cannot form the core-annulus flow structure;the fast inlet gas velocity leads to the back mixing of particles.In addition,as the inlet gas velocity increases,the gasphase velocity significantly increases and the particle velocity slowly increases.