空气净化机净化动力学分析及气流场数值模拟

Dynamic analysis and numerical simulation of internal wind field in air purification

采用动力学方法分析空气净化机理,对过滤网在吸收过程中的阻力进行了理论推导,为空气净化机滤纸、进出口风道的优化设计提供依据.从空气净化机内部气流场出发,建立内部气流场的几何模型,以多孔介质模型来模拟过滤网;通过Fluent软件数值模拟空气净化机内部气流,分析了进口风速在1～5m/s变化过程中,不同高度(0.05,0.10,0.15m)截面上的压力场和速度场变化.结果表明:风速在1～2m/s时,气流稳定;HEPA滤纸在高度为0.10m截面上对气流的阻力最大.为了获得更好的内部气流场,应尽量增大进风口和出风口的面积,使之覆盖的面积与主流风道大体一致,这样可减少涡流现象,并可降低出风口处的气流叠加效应.通过Fluent软件模拟效果良好,可为实际使用中的现场流场问题提供理论指导.

To provide foundation for optimal design of the filter and the inlet and outlet of the tunnel,dynamics method was used to analyze the mechanism of air purifier and deduce theoretically filter resistance in absorption process.Starting from the internal air flow field in an air purifier,a geometric model of internal wind field was built and porous medium was adopted to simulate the filter.Fluent software was applied to numerically simulate internal wind flow.The different values of pressure field and velocity field were measured and analyzed on three cross-sections of different heights（0.05 m,0.10 m and 0.15 m） with inlet velocity changing from 1 to 5 m/s.The results show that the wind flow remains steady when inlet velocity is 1-2 m/s,HEPA filter produces the strongest flow resistance at section of 0.10 m high.Therefore,the area of air inlet and outlet should be increased to be consistent with the main wind channel so as to get better internal flow field and meanwhile to avoid vortex phenomenon and lower flow superposition effect at the outlet.Fluent software simulation produces effective results and can provide theoretical basis for solving flow field issues in practice.