基于CFD的KN95口罩边缘泄漏率研究

Study on Leakage of KN95 Masks Based on CFD

针对口罩边缘泄漏问题,基于Ansys Fluent平台,利用SST k-ω模型和离散相模型,以KN95口罩为例,对颗粒物在口罩与脸部形成的泄漏缝隙中的流动情况进行模拟,研究了在不同呼吸强度下,不同粒径颗粒物经口罩边缘泄漏时,流体入口速度对口罩泄漏率的影响。结果表明:相同呼吸强度下,泄漏率随粒径增大而减小,呼吸强度较弱和较强两种条件下对应的颗粒物泄漏率随粒径增加分别呈现出快速和缓慢下降趋势;粒径小于0.5μm颗粒物的泄漏率随着呼吸强度增强先增大后减小,且粒径越小,泄漏率越高;对于粒径大于0.5μm的颗粒物,泄漏率随呼吸强度增强整体呈减小趋势,当入口速度介于0.3~0.7 m/s时,其泄漏率出现了明显的增加。

Based on Fluent 2020 R2,the SST k-ωmodel and Discrete Phase Model(DPM)were used to simulate the flow of particles in the leakage between the KN95 mask and the face,and the effect of fluid inlet velocity on the leakage rate was investigated under different respiratory intensities when particles of different sizes leaked through the edge.The results show that the leakage rate decreases with the increase of particle size under the same respiratory intensity,and shows rapid and slow decreasing trends with increasing particle size,respectively,under weak and strong respiration intensity.The leakage rate of particles less than 0.5 m firstly increases and then decreases with the enhancement of respiratory intensity,and the smaller the particle size,the higher the leakage rate.For particles larger than 0.5 m,the leakage rate tends to decrease with the enhancement of respiratory intensity,and increases significantly when the inlet velocity is among 0.3-0.7 m/s.