Numeral Simulation For Flow Field And Pressure Drop Character Of Diesel Particulate Filter

With the implementation of European VI emission standards,diesel particulate filters(DPF)will be widely used in diesel aftertreatment system as one of the most effective technologies to reduce emission of PM.Velocity and static pressure distribution of DPF channels can be acquired through analyzing the interior fluid field of DPF.Based on the acquired data,the soot loading process of DPF channels can be predicted.The regeneration process is the main problem in the related research of DPF,the pressure drop character directly affect the time of regeneration.So the fluid flow and pressure drop characters of DPF have important theoretical significance and engineering application value.Through this research,the flow and pressure drop characters of DPF can be obtained,which laid a solid foundation to optimize the structure of DPF.A 3-D model of diesel particulate filter with asymmetrical channels was established by Fluent.Based on numerical model,the fluid flow and pressure drop characteristics were simulated,the soot loading process was analysed,the pressure drop of asymmetrical channels and symmetrical channels was compared.The results show that: Along the inlet channels,the velocity magnitude increases at first then decreases while the static pressure decreases at first then increases;An increase of velocity magnitude is found along the outlet channels while the static pressure decresses;At the beginning of soot loading process,the downstream half of the channel has a larger amount of soot loading,then,as the increase of soot loading,the distribution of soot along the axial direction becomes uniform;The asymmetrical channels have a lower pressure drop while the coefficient of absolute soot loading is above 0.3;As the increase of inlet-outlet ratio,the pressure drop changing as a function of the inlet mass flow rate is more significant.A one-dimensional pressure drop model of DPF was established by AVL-Boost,the model was validated by experiment.Based on numerical model,the influence of structural parameters on DPF pressure drop were analysed.The simulation results show that: For a DPF with deterministic structural parameters,the change of overall pressure drop was mainly affected by soot depth pressure drop and soot cake pressure drop;Increasing CPSI while reducing the wall thickness will help to decrease the overall pressure drop and there is a optimal CPSI for DPF,in this article the optimal CPSI is 400;DPF with smaller ratio of length and diameter has a lower pressure drop;When the soot loading is above 6g/L,DPF with a larger inlet-outlet ratio has a lower pressure drop.