静电除尘器数值模拟

摘要

针对静电除尘器建立了其流场、电晕电场、颗粒荷电与运动的三维数值模型,流场采用时均Navier-Stokes方程和雷诺应力标准湍流模型,电晕电场采用非结构有限容积法,颗粒运动采用拉格朗日方法,颗粒荷电采用对荷电率方程进行积分的方法,颗粒湍流扩散采用随机轨道模型,颗粒的粒径分布采用Rosin-Rammler分布描述,模拟计算了实验电除尘器电场分布、流场分布以及颗粒运动,极板上的电流密度分布计算值与实验值符合良好,颗粒向极板运动的速度在距离极板面5 mm处的实验值与计算值也符合良好,在模型验证基础上,进一步分析了电除尘器内部流场的分布、颗粒的荷电特性与运动轨迹以及各个粒径的除尘效率.%A three dimensional numerical model was developed for the description of the physical processes in the electrostatic precipitator (ESP), including fluid flow, corona discharge, particle charging and particle dynamics. Fluid flow was solved using the time-averaged Navier-Stokes equation and the standard ice turbulent model. The electric field generated by corona discharge was solved using an unstructured finite volume method. Particle motion was modeled using the Lagrangian method. Particle charge was calculated by the integration of the charging rate equation. The Rosin-Rammler distribution was used to model particle size distribution. The model was verified by comparing the numerical results with the experimental data of a laboratory scale ESP. The model predictions of plate current density and particle transverse velocity agreed well with the measurements. Finally, the characteristics of fluid flow distribution, particle charging process, particle trajectories and collection efficiency were analyzed.