布袋过滤除尘中气固两相流的格子Boltzmann模拟

Numerical simulation of gas-solid two-phase flow on dust collection filters using Lattice Boltzmann Method

使用格子Boltzmann方法对含尘气体通过布袋滤料纤维的流动进行了数值模拟,采用拉格朗日方法跟踪了颗粒相中每个粒子的位置和速度并进行单向耦合计算。分析了气流通过纤维捕集体过程中的压降的变化规律,结果与达西渗透定律吻合。与此同时,对粒径小于1μm的气溶胶粒子在布袋纤维捕集体上的沉积规律展开了讨论。结果表明,粒径小于0.01μm的粒子的捕集主要受粒子的布朗随机扩散效应的控制;粒径大于0.1μm的粒子则主要依靠纤维滤料的拦截作用而沉积在捕集体表面;而粒径在0.01～0.1μm范围的粒子则具有较低的捕集效率。模拟结果为研究袋式除尘的过滤机理提供了依据。

The gas-solid two phase flow through the bag filter fibers was numerically simulated by Lattice Boltzmann Method. The one-way coupled technique was used to describe the particles＇ movement behavior ac-cording to the Lagrange method. The results indicate that the variation of pressure drop conforms to the Darcy＇ s law perfectly when gas flow passes through the porous media. The principles of the particulate （ diameter ≤ 1 μm） transportation and deposition on to the surfaces of the bag fiber were also discussed. The simulation results show that the collection efficiency varies with the particle diameter. When the particle diameter is less than 0.01 μm, the collection efficiency is quite high due to the strong Brownian diffusion effect. If the particle is greater than 0. 1 μm, the collection efficiency goes up too, since the interception mechanism of the fiber plays an impor-tant role for the big size particles. However, it is relatively difficult to trap the particles in the range from 0.01 μm to 0. 1 μm. The simulation is meaningful for the mechanism researches of bag-type dedust.