颗粒物在通风管道壁面上沉积的数值分析

为了探究颗粒物在通风管道壁面上的沉积特性,采用欧拉-拉格朗日方法,对粒径为0.003~30 um的颗粒在水平二维粗糙管道及光滑管道内的运动进行了模拟研究,并将两种情况的计算结果进行对比.首先,采用RSM模型得到两种管道内的时均流场,然后采用随机轨道模型得到颗粒物的运动轨迹并计算沉降速度.结果表明粗糙元增大了颗粒的沉降速度,对颗粒沉积的影响在粒径为1 um左右时最为显著,沉降速度提高约3个数量级,且在管道底面布置粗糙元还会增大顶部光滑壁面的颗粒沉降速度.

Numerical Analysis of Particle Deposition on Surfaces in Ventilation Ducts

In order to study the particle deposition on surfaces in ventilation ducts, the Eulerian- Lagrangian method was applied to simulate particles ranging from 0. 003 - 30 um deposition in a 2D horizontal rough duct and a smooth duct. The results were compared in both cases. Firstly, RSM model was used for mean flow field simulation of the two ducts. In addition, a discrete random walk model was used to predict particles＇ trajectories and the particle deposition velocity was calculated. The results indicated that roughness elements increased particle deposition velocity. The effect was significant when particle diameter was about 1 urn, and the particle deposition was increased about two magnitudes. Moreover, the duct with roughness elements at its floor can also increase particle deposition velocity at ceiling, although the ceiling is smooth.