Numerical simulations are performed both for the single airflow and air-PMtwo-phase flow in wall flow diesel participate filters (DPF) for the first time. The calculationdomain is divided into two regions. In. the inl...Numerical simulations are performed both for the single airflow and air-PMtwo-phase flow in wall flow diesel participate filters (DPF) for the first time. The calculationdomain is divided into two regions. In. the inlet and outlet flow channels, the simulations areperformed for the steady and laminar flow; In the porous filtration walls, the calculation model forflow in porous media is used. The Lagrange two-phase flow model is used to calculate the air-PMflow in DPF, for the dispersed phase (PM), its flow tracks are obtained by the integrating of theLagrange kinetic equation. The calculated velocity, pressure distribution and PM flow tracks in DPFare obtained, which exhibits the main flow characteristics in wall flow DPF and will be help for theoptimal design and performance prediction of wall flow DPF.展开更多
In this paper, a new method-Distributed La-grange Multiplier/fictitiousdomain (DLM) method for partic-ulate flows was improved. A rectangular mesh was introduced todiscretize the domain, and the buoyant force was cons...In this paper, a new method-Distributed La-grange Multiplier/fictitiousdomain (DLM) method for partic-ulate flows was improved. A rectangular mesh was introduced todiscretize the domain, and the buoyant force was considered for predicting the positions ofparticles. In order to validate the presented algorithm, the sedimentation of a single circularparticle was simulated using different mesh sizes and time steps firstly. The results show that thesimulation is independent of the mesh size as well as the time step. And then, the interactionsbetween two falling particles, including drafting, kissing and tumbling, and the sedimentation of 18particles also have been simulated with the code.展开更多
In the non-spherical particulate turbulent flows, a set of new fluidfluctuating velocity equations with the non-spherical particle source term were derived, then a newmethod, which treats the slowly varying functions ...In the non-spherical particulate turbulent flows, a set of new fluidfluctuating velocity equations with the non-spherical particle source term were derived, then a newmethod, which treats the slowly varying functions and rapidly varying functions separately, wasproposed to solve the equations, and finally the turbulent intensity and the Reynolds stress of theflu-id were obtained by calculating the fluctuating velocity statlsti-cally. The equations andmethod were used to a paniculate tur-bulent pipe flow. The results show that the turbulent intensityand the Reynolds stress are decreased almost inverse proportion-ally to the fluctuating velocityratio of particle to fluid. Non-spherical particles have a greater suppressing effect on thetur-bulence than the spherical particles. The particles with short re-laxation time reduce theturbulence intensity of fluid, while the particles with long relaxation time increase the turbulenceinten-sity of fluid. For fixed particle and fluid, the small particles sup-press the turbulence andthe large particles increase the turbu-ience.展开更多
文摘Numerical simulations are performed both for the single airflow and air-PMtwo-phase flow in wall flow diesel participate filters (DPF) for the first time. The calculationdomain is divided into two regions. In. the inlet and outlet flow channels, the simulations areperformed for the steady and laminar flow; In the porous filtration walls, the calculation model forflow in porous media is used. The Lagrange two-phase flow model is used to calculate the air-PMflow in DPF, for the dispersed phase (PM), its flow tracks are obtained by the integrating of theLagrange kinetic equation. The calculated velocity, pressure distribution and PM flow tracks in DPFare obtained, which exhibits the main flow characteristics in wall flow DPF and will be help for theoptimal design and performance prediction of wall flow DPF.
文摘In this paper, a new method-Distributed La-grange Multiplier/fictitiousdomain (DLM) method for partic-ulate flows was improved. A rectangular mesh was introduced todiscretize the domain, and the buoyant force was considered for predicting the positions ofparticles. In order to validate the presented algorithm, the sedimentation of a single circularparticle was simulated using different mesh sizes and time steps firstly. The results show that thesimulation is independent of the mesh size as well as the time step. And then, the interactionsbetween two falling particles, including drafting, kissing and tumbling, and the sedimentation of 18particles also have been simulated with the code.
文摘In the non-spherical particulate turbulent flows, a set of new fluidfluctuating velocity equations with the non-spherical particle source term were derived, then a newmethod, which treats the slowly varying functions and rapidly varying functions separately, wasproposed to solve the equations, and finally the turbulent intensity and the Reynolds stress of theflu-id were obtained by calculating the fluctuating velocity statlsti-cally. The equations andmethod were used to a paniculate tur-bulent pipe flow. The results show that the turbulent intensityand the Reynolds stress are decreased almost inverse proportion-ally to the fluctuating velocityratio of particle to fluid. Non-spherical particles have a greater suppressing effect on thetur-bulence than the spherical particles. The particles with short re-laxation time reduce theturbulence intensity of fluid, while the particles with long relaxation time increase the turbulenceinten-sity of fluid. For fixed particle and fluid, the small particles sup-press the turbulence andthe large particles increase the turbu-ience.
