Simulation study on the influence of porous media microstructure on a diesel particulate filter
To optimize the pore structure of a diesel particulate filter and improve its capture and pressure drop per-formance,a two-dimensional DPF pore microstructure model was established based on the pore size probability den-sity function and porosity distribution function.We considered the interception and diffusion mechanisms to calcu-late the deposition distribution and filtration efficiency of particles in the filter.Results revealed that the influence of porous media microstructure and inlet velocity on the filtration efficiency of soot particles was related to the parti-cle size.The initial capture efficiency of 100 nm particles decreased with an increase in inlet velocity.The differ-ence in filtration efficiency of 1 000 nm particles under different heterogeneous filter walls exceeded 30％.The lar-ger the variance of pore size distribution,the greater the number of particles distributed in front of the filter wall,and the higher the filtration efficiency can be realized.However,excessive variance of pore size distribution would lead to an increase in initial pressure drop and serious deterioration of the pressure drop performance of the filter at the end of the filtering process.
particulate filternumerical simulationmicrostructureprobability density functionpressure dropfil-tration efficiency
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