旋风单管排尘锥内颗粒沉积黏附的数值研究

摘要

Based on theory and numerical simulation,a particle-wall adhesion model in vane cyclone tube was established to study the effect of throughput,temperature,particle concentration in gas feed and particle size on particle-wall adhesion in the discharge cone.Investigation shows that the shear ve-locity of flow near the wall is the critical factor for particle adhesion.With increasing the rate of feed, shear velocity of the gaseous flow near the wall increases greatly and the concentration of particles close to the wall rises,leading to more particle-wall adhesion.Operation parameters and solid properties af-fect the particle-wall adhesion.The influence of operation temperature is mainly through changing the Young modulus of particles,which declines significantly with operation temperature rising,resulting in more adhesion. Besides,the higher the particle concentration,the more collision and discharge cone scaling will occur.Particles of diameters between 1 "m and 10 "m are apt to deposit on discharge cone due to stay for a long time.%采用数值模拟与理论分析的方法，建立了旋风单管内的颗粒壁面沉积黏附模型，在此基础上考察了处理量、操作温度、进料浓度、进料粒度等因素对排尘锥颗粒沉积的影响规律。结果表明：边壁气流剪切速度是影响颗粒沉积的关键，处理量增加，边壁处被分离颗粒浓度升高，且近壁气流剪切速度增大，排尘锥颗粒沉积黏附增加；操作参数及进料参数均影响颗粒壁面沉积，其中操作温度主要通过影响颗粒杨氏模量对颗粒壁面沉积黏附产生影响，温度升高导致颗粒杨氏模量降低，颗粒壁面沉积增加；进料浓度增加，颗粒与壁面碰撞几率增加，使得排尘锥段颗粒沉积加剧；1～10"m的微颗粒在排尘锥内滞留时间较长，易于沉积黏附。