椭圆纤维对粒子拦截捕集特性的数值计算与分析

Numerical Calculation and Analysis of Particles Interception Characteristics by Elliptical Fibers

采用数值方法求解描述椭圆纤维绕流特征的Navier"Stokes方程,计算了椭圆纤维无量纲过滤阻力、拦截效率及纤维表面粒子沉积分布,引入质量因子评价椭圆纤维的综合过滤性能。分析讨论了椭圆纤维迎风角度(θ)、长短轴比(ε)以及填充率(C)对粒子过滤性能的影响。结果表明,对于高长短轴比的扁长椭圆纤维体,在θ=0°时,粒子主要沉积于纤维的前边缘区域,随着θ增大,粒子的沉积分布由纤维前边缘区域向两侧边缘聚集,在θ=90°时,纤维前驻点邻近区域几乎无粒子沉积。椭圆纤维质量因子分析结果则表明,迎风角度、长短轴比以及纤维填充率均对质量因子有显著影响,通过优化椭圆纤维的结构参数(即θ和ε)可获得优于传统圆截面纤维的综合过滤性能。

A numerical scheme was developed for calculating the elliptical fiber filtration resistance,interception efficiency of particles and the particle number distributions across a single elliptical fiber.The airflow around elliptical fibers used in computing interception efficiency was determined by solving the Navier-Stokes equation numerically.The quality factors(Q),were used to evaluate the performance of the elliptical fibers.The effects of the packing density(C),elliptical fiber’s crosssection aspect ratio(ε)and orientation angle(θ)on filtration performance were discussed.The results show that the collected particles are distributed mainly at the leading edge of fiber whenθ=0°for elliptical fiber with larger aspect ratio,whereas an increase in orientation angle leads to the particles deposition shifting from the leading edge to the lateral ledges of the elliptical fiber and,few particles depositing on the areas near the stagnation point atθ=90°.The calculated Qshow that a better filtration performance compared to the cylinder fiber with the same packing density can be achieved by optimizing the structural parameters(θandε)of the elliptical fiber.