数值模拟分解炉气流紊动特性及对颗粒运动的影响

Numerical Simulation of Flow Turbulence Characteristics in Precalciner and Effect on Particle Motion

为了系统分析分解炉内窑尾烟气与三次风的掺混流态及影响煤粉、料粉颗粒运动的规律,利用紊流模型与粒子追踪模型的数值模拟方法,研究了分解炉气流紊流强度、涡量及螺旋度的沿程分布规律及颗粒的运动规律,研究表明:①窑尾烟气与三次风的耦合作用,导致掺混区的气流流态表现出强紊动特性;②紊动区内颗粒发生强烈地脉动现象;③窑尾烟气与三次风的掺混作用、边壁条件的变化均能激发颗粒的绕轴旋转特性;④煤粉与料粉颗粒在分解炉内进行“螺旋式”上升或下降运动。

In order to systematically analyze mixing flow pattern of gas from a rotary kiln and tertiary airs in a precalciner and its influence on movements of pulverized and powder particles,laws of turbulence intensity,vorticity,helicity and particle motion along flow paths were studied by numerical simulations,which were the turbulence model and the particle tracking model.The results show these as follows.①Combined actions of exhaust gases from the rotary kiln and tertiary airs resulted in strong turbulent flow patterns in the mixing zone;②Strong fluctuations of particles occurred in the turbulent zone;③The combined actions of exhaust gases from the rotary kiln and tertiary airs could stimulate rotational characteristics of particles around an axis with variations of the side wall;④Pulverized coal and powder particles in the precalciner carried out spiral up or down movements.