Fluid-structure-particle interactions in three spatial dimensions happen in many environmental and engineering flows.This paper presents the parallel algorithms for the hybrid diffuse and sharp interface immersed boun...Fluid-structure-particle interactions in three spatial dimensions happen in many environmental and engineering flows.This paper presents the parallel algorithms for the hybrid diffuse and sharp interface immersed boundary(IB)method developed in our previous work.For the moving structure modeled using the sharp interface IB method,a recursive box method is developed for efficiently classifying the background grid nodes.For the particles modeled using the diffuse interface IB method,a‘master-slave’approach is adopted.For the particle-particle interaction(PPI)and particle-structure interaction(PSI),a fast algorithm for classifying the active and inactive Lagrangian points,which discretize the particle surface,is developed for the‘dry’contact approach.The results show that the proposed recursive box method can reduce the classifying time from 52seconds to 0.3 seconds.Acceptable parallel efficiency is obtained for cases with different particle concentrations.Furthermore,the lubrication model is utilized when a particle approaches a wall,enabling an accurate simulation of the rebounding phenomena in the benchmark particle-wall collision problem.At last,the capability of the proposed computational framework is demonstrated by simulating particle-laden turbulent channel flows with rough walls.展开更多
The shape of particles has a significant influence on the behavior of suspensions,as the particle-fluid,particle-particle,and particle-wall interactions depend on it.However,the simultaneous consideration of complex p...The shape of particles has a significant influence on the behavior of suspensions,as the particle-fluid,particle-particle,and particle-wall interactions depend on it.However,the simultaneous consideration of complex particle shapes and four-way coupling remains a major challenge.This is mainly due to a lack of suitable contact models.Contact models for complex shapes have been proposed in literature,and most limit the accuracy of the particle-fluid interaction.For this reason,this paper presents a novel contact model for complex convex particle shapes for use with partially saturated methods,in which we propose to obtain necessary contact properties,such as the indentation depth,by a discretization of the contact area.The goal of the proposed model is to enable comprehensive and accurate studies of particulate flows,especially with high volume fractions,that lead to new insights and contribute to the improvement of existing industrial processes.To ensure correctness and sustainability,we validate the model extensively by studying cases with and without fluid.In the latter case,we use the homogenized lattice Boltzmann method.The provided investigations show a great agreement of the proposed discrete contact model with analytical solutions and the literature.展开更多
How catalyst shape affects its deactivation is a crucial issue for quickly decaying catalysts such as zeolite in 2-butene and isobutane alkylation.In this work,steady simulations are used to determine the temperature ...How catalyst shape affects its deactivation is a crucial issue for quickly decaying catalysts such as zeolite in 2-butene and isobutane alkylation.In this work,steady simulations are used to determine the temperature and species distribution in fixed beds filled with particles of four shapes.Subsequently,unsteady simulations are used to study the deactivation behavior of the catalysts based on the steady simulation results.We describe the deactivation rate and type of catalyst deactivation by defining a local internal diffusivity,which is affected by catalytic activity.The results reveal that the internal diffusion distance of the catalyst determines the deactivation rate,whereas the local internal diffusivity determines its deactivation type.展开更多
A numerical study of the parameters controlling the viscous penalty method is investigated to better set up Particle-Resolved Direct Numerical Simulations (PR-DNS) of particulate flows. Based on this analysis, improve...A numerical study of the parameters controlling the viscous penalty method is investigated to better set up Particle-Resolved Direct Numerical Simulations (PR-DNS) of particulate flows. Based on this analysis, improvements of the methods are proposed in order to reach an almost second order convergence in space. The viscous penalty method is validated in Stokes regime by simulating a uniform flow past a fixed isolated cylinder. Moreover, it is also utilized in moderate Reynolds number regime for a uniform flow past a square configuration of cylinder and compared in terms of friction factor to the well-known Ergun correlation.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.12202456 and12172360)the Basic Science Center Program for“Multiscale Problems in Nonlinear Mechanics”of the National Natural Science Foundation of China(No.11988102)the China Postdoctoral Science Foundation(No.2021M693241)。
文摘Fluid-structure-particle interactions in three spatial dimensions happen in many environmental and engineering flows.This paper presents the parallel algorithms for the hybrid diffuse and sharp interface immersed boundary(IB)method developed in our previous work.For the moving structure modeled using the sharp interface IB method,a recursive box method is developed for efficiently classifying the background grid nodes.For the particles modeled using the diffuse interface IB method,a‘master-slave’approach is adopted.For the particle-particle interaction(PPI)and particle-structure interaction(PSI),a fast algorithm for classifying the active and inactive Lagrangian points,which discretize the particle surface,is developed for the‘dry’contact approach.The results show that the proposed recursive box method can reduce the classifying time from 52seconds to 0.3 seconds.Acceptable parallel efficiency is obtained for cases with different particle concentrations.Furthermore,the lubrication model is utilized when a particle approaches a wall,enabling an accurate simulation of the rebounding phenomena in the benchmark particle-wall collision problem.At last,the capability of the proposed computational framework is demonstrated by simulating particle-laden turbulent channel flows with rough walls.
基金The research leading to these results was conducted during the IGF Project AiF 21096 N of the FEI that has been supported via AiF within the programme for promoting the Industrial Collective Research(IGF)of the Federal Ministry of Economic Affairs and Climate Action(BMWK)based on a resolution of the German Parliament.
文摘The shape of particles has a significant influence on the behavior of suspensions,as the particle-fluid,particle-particle,and particle-wall interactions depend on it.However,the simultaneous consideration of complex particle shapes and four-way coupling remains a major challenge.This is mainly due to a lack of suitable contact models.Contact models for complex shapes have been proposed in literature,and most limit the accuracy of the particle-fluid interaction.For this reason,this paper presents a novel contact model for complex convex particle shapes for use with partially saturated methods,in which we propose to obtain necessary contact properties,such as the indentation depth,by a discretization of the contact area.The goal of the proposed model is to enable comprehensive and accurate studies of particulate flows,especially with high volume fractions,that lead to new insights and contribute to the improvement of existing industrial processes.To ensure correctness and sustainability,we validate the model extensively by studying cases with and without fluid.In the latter case,we use the homogenized lattice Boltzmann method.The provided investigations show a great agreement of the proposed discrete contact model with analytical solutions and the literature.
基金We acknowledge financial support from National Engineering Research Center for Petroleum Refining Technology and Catalyst(RIPP,SINOPEC,Grant No.33600000-20-ZC0607-0009).
文摘How catalyst shape affects its deactivation is a crucial issue for quickly decaying catalysts such as zeolite in 2-butene and isobutane alkylation.In this work,steady simulations are used to determine the temperature and species distribution in fixed beds filled with particles of four shapes.Subsequently,unsteady simulations are used to study the deactivation behavior of the catalysts based on the steady simulation results.We describe the deactivation rate and type of catalyst deactivation by defining a local internal diffusivity,which is affected by catalytic activity.The results reveal that the internal diffusion distance of the catalyst determines the deactivation rate,whereas the local internal diffusivity determines its deactivation type.
文摘A numerical study of the parameters controlling the viscous penalty method is investigated to better set up Particle-Resolved Direct Numerical Simulations (PR-DNS) of particulate flows. Based on this analysis, improvements of the methods are proposed in order to reach an almost second order convergence in space. The viscous penalty method is validated in Stokes regime by simulating a uniform flow past a fixed isolated cylinder. Moreover, it is also utilized in moderate Reynolds number regime for a uniform flow past a square configuration of cylinder and compared in terms of friction factor to the well-known Ergun correlation.
