应用随机轨道模型研究颗粒在通风管道内的沉积

Using Discrete Random Walk Model to Study the Particle Deposition in Ventilation Duct

本文采用欧拉—拉格朗日法模拟了纳米—微米级颗粒在竖直以及水平通风管道中的沉积。首先,采用常用的RNG k-ε两方程模型得到了时均流场,采用单向耦合的随机轨道模型产生了脉动速度并模拟了流场—颗粒之间的作用。而后,针对RNG k-ε两方程模型会过高估计在扩散区以及扩散—碰撞区颗粒沉积速度的问题,提出了简便的修正方法,并与文献中的经验公式以及试验数据进行了对比。结果表明,应用本文提出的修正方法可以极大地提高欧拉—拉格朗日法模拟颗粒沉积的准确度。

In this paper,a series of numerical simulations were conducted to study the deposition of nano-and micro-particles in ventilation duct using Euler-Lagrangian method.Firstly,the mean flow field and turbulent properties were generated using RNG k-ε turbulence model.In addition,a one-way coupling discrete random walk model was used to predict velocity fluctuations and particle-eddy interaction.Furthermore,according to the problem that RNG k-ε model without near-wall correction would over-predict particle deposition velocity in the diffusion and diffusion-impaction regime,a simple near-wall correction for RNG k-ε model was proposed,also the simulation results with and without the near-wall correction were compared with the available experimental data and empirical equations in the literature.The results indicated that using the near-wall correction proposed in this paper would greatly improve the accuracy of particle deposition velocity in the diffusion and diffusion-impaction regime.