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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。
Pressure drop is an important indicator to evaluate the performance of filter. Aimed at the process of capturing fine particles by wall-flow filter, a one-dimensional unsteady model describing the distribution of flow field and particle layer in the channel was established. Through the numerical calculation, the effect of particle slip on the particle distribution and pressure drop was studied. At the same time, the effect of filter structure parameters and flow parameters on filtration pressure drop was studied. The results show that the distribution of particle layer directly affects the pressure drop of filtration. With the enhancement of particle slip effect, the particle layer increases from flat to straight line, while the pressure drop increases first and then decreases. The increase of filter length helps to reduce Filter pressure drop; increasing the number of filter holes mesh, increasing the pressure drop during the initial stage of the filter work, but can reduce the filtration pressure drop when the deposition of high particles; in addition, with the flow rate and particle concentration increases, the filtration pressure drop increase.