壁流式过滤体捕集微细颗粒过程的数值模拟

压降是评价过滤体性能的重要指标。针对壁流式过滤体捕集微细颗粒物的过程,建立了描述通道内流场和颗粒层分布的一维非稳态模型。通过数值计算,研究了颗粒层滑移对颗粒层分布和过滤压降的影响,同时研究了过滤体结构参数与来流参数对过滤压降的影响。研究结果表明:颗粒层分布直接影响过滤压降,随着颗粒层滑移效应的加强,颗粒层由平坦转向直线递增型分布,过滤压降则先增后降;增加过滤体长度有助于降低过滤压降;增加过滤体孔目数,增加了过滤体工作初始阶段的压降,但可降低高颗粒沉积量时的过滤压降;此外,随来流流量和颗粒浓度的增加,过滤压降增加。

Numerical simulation of fine particles trapping process using a wall-flow honeycomb filter

Pressure drop is a key parameter for evaluating filter performance.A one-dimensional unsteady model was developed to simulate the trapping of fine particles by a wall-flow filter by simulating the flow field and particle layer distribution in a channel.The numerical simulations showed the influence of particle layer migration on the particle layer distribution and filter pressure drop,along with the influence of filter configuration and inlet flow parameters on the filter pressure drop.The results show that the particle layer distribution directly influences the filter pressure drop.With stronger particle layer migration,the particle layer distribution varies from flat to linearly increasing with the filter pressure drop increasing slowly at first and then decreasing.Increases in the filter length reduce the filter pressure drop,while increases in the filter cell density increase the initial filter pressure drop,but reduce the filter pressure drop at high particle loads.Increases in the inlet flow rate or the particle concentration both increase the filter pressure drop.