Simulation Study On Trapping And Regeneration Characteristics Of Asymmetric Channel DPF

Diesel engines are widely used in today’s industrialized production and life because of their strong power and high economy,but the particulates in the exhaust seriously harm the environment and human health.DPF(Diesel Particular Filter)has become an important configuration in the diesel engine aftertreatment system,and simple and reliable DPF regeneration is the key to the development of DPF technology.The use of an asymmetric channel structure DPF can effectively reduce the pressure drop at higher carbon load and extend the regeneration interval of DPF.In this paper,through the combination of test and simulation,the pressure drop and regeneration characteristics of the asymmetric pore carrier DPF are comparatively studied,and the influencing factors of the DPF capture process and regeneration process are analyzed to provide a theoretical basis for the development and performance optimization of high-performance DPF carriers.In this paper,the DPF with asymmetric pore and symmetric pore structure is taken as the research object,and the DPF pressure drop characteristic test is carried out,meanwhile the pressure drop under the clean state of the two DPFs is compared with the exhaust flow rate,and the relationship between the pressure drop of the two DPFs with time.The research results show that the pressure drop of the asymmetric channel DPF is higher than that of the symmetric structure DPF at the beginning of the capture process.However,with the increase of the collection time,the pressure drop of the asymmetric channel DPF will gradually be lower than that of the symmetric channel DPF.There is a pressure drop intersection during the process.Increasing the exhaust mass flow will delay the pressure drop intersection and increase the exhaust temperature.The carbon load corresponding to the pressure drop intersection will decrease first and then increase.The simulation software GT-POWER was used to establish soot capture and thermal regeneration models with different import and export ratios of DPF,and the model parameters are revised in conjunction with the test data.The soot capturing model is used to analyze the effect of the asymmetric channel DPF inlet and outlet channel ratio and other structuralparameters on the pressure drop characteristics and capturing efficiency of the trapping process.The results show that as the proportion of inlet and outlet channels increases,the pressure drop in the later stage of the capture process becomes smaller.The longer the DPF length,the smoother the pressure drop rise curve.The greater the DPF pressure drop,the greater the DPF pressure drop,and also the lower wall thickness will result in lower filtration efficiency in the early stage of the capture process.Increasing the mesh size will increase the DPF filtration efficiency,but will cause an increase in pressure drop.In the early DPF trap,the pressure drop in the inlet and outlet channels accounts for The proportion of pressure drop is high,so as the proportion of imports and exports increases,the greater the DPF pressure drop.However,in the late period of DPF trapping,the proportion of carbon smoke layer drop increased,resulting in a lower pressure drop as the proportion of imports and exports increased.The thermal regeneration model was used to study the temperature field distribution of the DPF regeneration process,as well as the influence of the inlet and outlet channel ratio and operating parameters on the regeneration process.The research results show that with the regeneration process,there is obvious temperature stratification in the regeneration stage.The peak temperature of DPF wall moves from the front end of the axial position of the filter body to the end position.The soot in the front end of DPF is oxidized first,and after the regeneration,there are still some soot at the radial edge that has not been oxidized.With the increase of the proportion of the inlet and outlet channels,the regeneration duration decreases,but the peak of the wall also decreases.The peak wall temperature increases with the increase of regeneration heating temperature and soot accumulation,and decreases slightly with the increase of inlet flow rate.Increasing the oxygen concentration in the regeneration gas within a certain range helps to improve the overall regeneration rate and regeneration efficiency,but it will produce a higher wall temperature.