In this paper, the effects of channel roughness on the droplet removal efficiency and pressure drop in a zigzag mist eliminator are investigated. The fluid flow, droplet dispersion and deposition through the demister are modelled using a commercial Computational Fluid Dynamics (CFD) tool. The turbulent airflow is simulated using two different Shear-stress Transport (SST) k-ω model and Reynolds Stress Model (RSM) with enhanced wall treatment. The Eddy Interaction Model (EIM) is also used to predict the trajectories of the droplets in the gas flow. The results show that inserting roughness increases the maximum velocity of the gas flow at the bends and enhances the removal efficiency with a little cost of an increase in the pressure drop for each bend. At the velocity inlet of 2 m/s with 6 μm droplets, the pressure drop and removal efficiency of the threaded zigzag demister with 5 threads increases by 22.7% and 16.08 %, respectively. Moreover, a higher value for the figure of merit is achieved for the threaded demister compared with the smooth unit which means that the effect of higher removal efficiency of the threaded unit is more pronounced than the effect of higher pressure drop showing the advantages of adding threads in demisters.

本文研究了锯齿形除雾器中通道粗糙度对液滴去除效率和压降的影响。通过除雾器的流体流动，液滴分散和沉积是使用商业计算流体动力学（CFD）工具建模的。使用两种不同的剪切应力传递（SST）k-ω模型和增强壁处理的雷诺应力模型（RSM）模拟湍流。涡流相互作用模型（EIM）也用于预测气流中液滴的轨迹。结果表明，插入粗糙度可以增加弯头处气流的最大速度，并提高去除效率，而每个弯头的压降增加的成本却很少。在2 m / s的速度入口处有6μm的液滴，5根螺纹锯齿形除雾器的压降和去除效率分别提高了22.7％和16.08％。而且，与平滑单元相比，螺纹除雾器的品质因数更高，这意味着螺纹单元的较高去除效率的效果比较高压降的效果更为明显，这表明增加了螺纹的优势在除雾器中。