Taking wall-flow diesel particulate filter(DPF) as the research objective and separately assuming its filtering wall to be composed of numerous spherical or cylindrical elements, two different mathematical models of s...Taking wall-flow diesel particulate filter(DPF) as the research objective and separately assuming its filtering wall to be composed of numerous spherical or cylindrical elements, two different mathematical models of steady filtration for wall-flow diesel particulate filter were developed and verified by experiments as well as numerically solved. Furthermore, the effects of the macroand micro-structural parameters of filtering wall and exhaust-flow characteristic parameters on trapping efficiency were also analyzed and researched. The results show that: 1) The two developed mathematical models are consistent with the prediction of variation of particulate size; the influence of various factors on the steady trapping efficiency is exactly the same. Compared to model 2, model 1 is more suitable for describing the steady filtration process of wall-flow diesel particulate filter; 2)The major influencing factors on steady trapping efficiency of wall-flow diesel particulate filter are the macro-and micro-structural parameters of filtering wall; and the secondary influencing factors are the exhaust-flow characteristic parameters and macro-structural parameters of filter; 3)The steady trapping efficiency will be improved by increasing filter body volume, pore density as well as wall thickness and by decreasing exhaust-flow, but effects will be weakened when particulate size exceeds a certain critical value; 4) The steady trapping efficiency will be significantly improved by increasing exhaust-flow temperature and filtering wall thickness, but effects will be also weakened when particulate size exceeds a certain critical value; 5) The steady trapping efficiency will approximately linearly increase with reducing porosity, micropore aperture and pore width.展开更多
A three-dimensional diesel particulate filter(DPF)simulation model was developed by using AVL software FIRE to study the effects of four factors on soot particle distributions along the axial and radial directions in ...A three-dimensional diesel particulate filter(DPF)simulation model was developed by using AVL software FIRE to study the effects of four factors on soot particle distributions along the axial and radial directions in the DPF after the model accuracy was validated.An orthogonal test method was used to determine the importance and weights of the design of experiments(DoE)factors such as the expanding angle,the number of channels per square inch,and the exhaust mass flow rate.The effects of these factors on the uniformity of the soot particle distributions were also analyzed.The results show that when the soot loading time was 400 s,the soot particles inside the DPF along the axial direction exhibited a bowl shape,which was high on the both ends and low in the middle.The uniformity of the axial distribution of soot particles reduces significantly with an increase in the number of channels per square inch.The uniformity of the radial distribution reduced with an increase in the expanding angle of the divergent tube.Based on the impacts on the axial uniformity,the three most influencing factors in a descending order are the number of channels per square inch,the exhaust mass flow rate,and the expanding angle of the divergent tube.展开更多
Numerical simulation has been carried out to investigate the major factors affecting the time of composite regeneration due to coupling cerium-based additive and microwave for diesel particulate f3ilter(DPF). Effect o...Numerical simulation has been carried out to investigate the major factors affecting the time of composite regeneration due to coupling cerium-based additive and microwave for diesel particulate f3ilter(DPF). Effect on the composite regeneration time from various factors such as mass flow rate of exhaust gas, temperature of exhaust gas, oxygen concentration of exhaust gas, microwave power and amount of cerium-based additive are investigated. And a mathematical model based on fuzzy least squares support vector machines has been developed to forecast the endpoint of the composite regeneration. The results show that the relative error of endpoint forecasting model of composite regeneration is less than 3.5%, and the oxygen concentration of exhaust gas has the biggest effect on the endpoint of composite regeneration, followed by the mass flow rate of exhaust gas, the microwave power, the temperature of exhaust gas and the amount of cerium-based additive.展开更多
基金Projects(5117604551276056)supported by the National Natural Science Foundation of China+1 种基金Projects(201208430262201306130031)supported by the National Studying Abroad Foundation of the China Scholarship Council
文摘Taking wall-flow diesel particulate filter(DPF) as the research objective and separately assuming its filtering wall to be composed of numerous spherical or cylindrical elements, two different mathematical models of steady filtration for wall-flow diesel particulate filter were developed and verified by experiments as well as numerically solved. Furthermore, the effects of the macroand micro-structural parameters of filtering wall and exhaust-flow characteristic parameters on trapping efficiency were also analyzed and researched. The results show that: 1) The two developed mathematical models are consistent with the prediction of variation of particulate size; the influence of various factors on the steady trapping efficiency is exactly the same. Compared to model 2, model 1 is more suitable for describing the steady filtration process of wall-flow diesel particulate filter; 2)The major influencing factors on steady trapping efficiency of wall-flow diesel particulate filter are the macro-and micro-structural parameters of filtering wall; and the secondary influencing factors are the exhaust-flow characteristic parameters and macro-structural parameters of filter; 3)The steady trapping efficiency will be improved by increasing filter body volume, pore density as well as wall thickness and by decreasing exhaust-flow, but effects will be weakened when particulate size exceeds a certain critical value; 4) The steady trapping efficiency will be significantly improved by increasing exhaust-flow temperature and filtering wall thickness, but effects will be also weakened when particulate size exceeds a certain critical value; 5) The steady trapping efficiency will approximately linearly increase with reducing porosity, micropore aperture and pore width.
基金Project(52066008)supported by the National Natural Science Foundation,ChinaProject(2018FA030)supported by Yunnan Province Fundamental Research Key Project Foundation,China+1 种基金Project(2018ZE001)supported by Yunnan Province Major Science and Technology Project Foundation,ChinaProject(202005AG070057)supported by Yunnan Province Science and Technology Innovation Funds for key Laboratories,China。
文摘A three-dimensional diesel particulate filter(DPF)simulation model was developed by using AVL software FIRE to study the effects of four factors on soot particle distributions along the axial and radial directions in the DPF after the model accuracy was validated.An orthogonal test method was used to determine the importance and weights of the design of experiments(DoE)factors such as the expanding angle,the number of channels per square inch,and the exhaust mass flow rate.The effects of these factors on the uniformity of the soot particle distributions were also analyzed.The results show that when the soot loading time was 400 s,the soot particles inside the DPF along the axial direction exhibited a bowl shape,which was high on the both ends and low in the middle.The uniformity of the axial distribution of soot particles reduces significantly with an increase in the number of channels per square inch.The uniformity of the radial distribution reduced with an increase in the expanding angle of the divergent tube.Based on the impacts on the axial uniformity,the three most influencing factors in a descending order are the number of channels per square inch,the exhaust mass flow rate,and the expanding angle of the divergent tube.
基金Projects(51176045,51276056)supported by the National Natural Science Foundation of ChinaProject(201208430262)supported by the National Studying Abroad Foundation Project of China
文摘Numerical simulation has been carried out to investigate the major factors affecting the time of composite regeneration due to coupling cerium-based additive and microwave for diesel particulate f3ilter(DPF). Effect on the composite regeneration time from various factors such as mass flow rate of exhaust gas, temperature of exhaust gas, oxygen concentration of exhaust gas, microwave power and amount of cerium-based additive are investigated. And a mathematical model based on fuzzy least squares support vector machines has been developed to forecast the endpoint of the composite regeneration. The results show that the relative error of endpoint forecasting model of composite regeneration is less than 3.5%, and the oxygen concentration of exhaust gas has the biggest effect on the endpoint of composite regeneration, followed by the mass flow rate of exhaust gas, the microwave power, the temperature of exhaust gas and the amount of cerium-based additive.
