含尘单纤维过滤捕集效率的数值模拟

Numerical Simulation of Collection Efficiency of a Particle-Loaded Single Fiber

利用单纤维过滤介质表面颗粒沉积的随机计算模型,通过离散相模型(DPM)模拟方法,讨论单纤维非稳态过滤过程中捕集效率随沉积颗粒数增加的变化情况,模拟分析了颗粒沉积形态、斯托克斯数(St)、无量纲粒径(Nr)及纤维雷诺数(Ref)对含尘单纤维捕集效率的影响.研究结果表明:在过滤的初始阶段,St值对单纤维捕集效率起决定作用,St值越大,捕集效率越高;随着过滤的进行,单纤维的捕集效率随沉积颗粒数的增多而增加,其线性关系及增长的幅度与St、Ref和Nr有关,且相同情况下,沉积的颗粒在迎风面上形成的横截面积越大,则越有利于颗粒的捕集.

By using stochastic simulation technique in the growing process of particle dendrites on a single fiber,through the discrete phase model（DPM）simulation technique,the impact of particle dendrites on collection efficiency of a single fiber was discussed,during the unsteady filtering state.The effects of Stokes number（St）,dimensionless particle diameter（Nr）,Reynolds of fiber（Ref）and particle dendrites morphology on collection efficiency were investigated.The results show that the collection efficiency of a single fiber strongly depends on St in the early stage of the deposition and simulation cases with higher value of St has greater efficiency.As the process of deposition going on,the collection efficiency of a single fiber increases with the number of particles on the fiber,and the linear relationship and growth rate are related to the value of St,Refand Nr.In addition,the deposition morphology that has a greater block district on the windward side is conductive to capturing particles.