A numerical scheme was developed for calculating single fiber drag force and inertial capture efficiencies of particles,and the viscous flow fields inside a model filter composed by staggered fiber arrays were determined by solving the Navier-Stokes equation numerically.The drag force of single fiber was then calculated for various values of packing density (C) and Reynolds number,and compared with the theoretical predictions by Happel and Kuwabara models,respectively.The results showed that Happel model agreed reasonably well with present numerical calculations when C ＜ 0.045,giving a better prediction than that by Kuwabara model,while Kuwabara model was more reliable for C ＞ 0.08.The single fiber collection efficiency due to inertial impaction was also obtained from the rigorous numerical simulations of trajectories of particles based on the viscous flow field solved by numerical simulations,and the effects of filtration velocity,particle density and packing density were discussed.The results showed that there was a critical particle diameter for inertial collection,below which particles failed to be captured by fibers.Based on the simulation results,a new correlation equation for predicting the single fiber drag force was presented,and a new correlation for single fiber efficiency due to inertial impaction was derived as a function of Stokes number (St) and C for St ≤10and 0.01≤C ≤0.1.%采用数值方法求解了描述交错排列纤维模型过滤器绕流特征的Navier-Stokes方程,并计算分析了纤维表面粒子的惯性捕集效率和单纤维过滤阻力.结果指出,在填充率C＜0.045时,Happel过滤阻力模型与数值结果十分吻合,优于Kuwabara模型给出的估计;当纤维填充率C＞0.08时,Kuwabara模型的预测结果与数值结果更接近.通过追踪粒子的运动轨迹计算了单纤维的惯性捕集效率,讨论了过滤风速、粒子密度和填充率对粒子惯性捕集效率的影响.结果表明,粒子的惯性捕集作用存在某一临界粒子直径,小于临界直径的粒子将不被捕集;根据数值分析结果,分别给出了一个可适用于单纤维阻力估计的关系式和惯性捕集效率的计算公式,其适用参数范围为St≤10(Stokes数)和0.01≤C≤0.1.
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