This article presents the development and validation of the Superquadric Discrete Element Method(SuperDEM)for non-spherical particle simulation using a superquadric particle method in open-source CFD suite MFiX.A supe...This article presents the development and validation of the Superquadric Discrete Element Method(SuperDEM)for non-spherical particle simulation using a superquadric particle method in open-source CFD suite MFiX.A superquadric particle-particle contact algorithm with accelerating and stabilizing strategy was developed.A superquadric particle-arbitrary wall contact algorithm was developed,which enables the simulation in complex geometry.The solver was validated by comparing with experimental data generated in this study or available in the literature.Tests include cylinder contacting with a wall,static packing of M&M chocolate candies in a cylindrical container,static packing of cylinders in a cylindrical container,dynamic angle of repose of cylinders in a rotating drum,and discharging of chocolate candies from a hopper.Besides,MPI parallelization of the solver was implemented and the parallel performance of the solver using MPI was assessed through large-scale simulations of 1 million,10 million,and 100 million particles on up to 6800 cores,which demonstrates that the SuperDEM solver has great potential for industrial-scale systems simulation.展开更多
The research on the coupling method of non-spherical granular materials and fluids aims to predict the particle-fluid interaction in this study.A coupling method based on superquadric elements is developed to describe...The research on the coupling method of non-spherical granular materials and fluids aims to predict the particle-fluid interaction in this study.A coupling method based on superquadric elements is developed to describe the interaction between non-spherical solid particles and fluids.The discrete element method(DEM)and the smoothed particle hydrodynamics(SPH)are adopted to simulate granular materials and fluids.The repulsive force model is adopted to calculate the coupling force and then a contact detection method is established for the interaction between the superquadric element and the fluid particle.The contact detection method captures the shape of superquadric element and calculates the distance from the fluid particle to the surface of superquadric element.Simulation cases focusing on the coupling force model,energy transfer,and large-scale calculations have been implemented to verify the validity of the proposed coupling method.The coupling force model accurately represents the water entry process of a spherical solid particle,and reasonably reflects the difference of solid particles with different shapes.In the water entry process of multiple solid particles,the total energy of the water entry process of multiple solid particles tends to be stable.The collapse process of the partially submerged granular column is simulated and analyzed under different parameters.Therefore,this coupling method is suitable to simulate fluid-particle systems containing solid particles with multiple shapes.展开更多
In the previous work, an efficient method has been proposed to represent solid objects as multiple combinations of globally deformed supershapes. In this paper, this framework is applied with a new supershape implicit...In the previous work, an efficient method has been proposed to represent solid objects as multiple combinations of globally deformed supershapes. In this paper, this framework is applied with a new supershape implicit function that is based on the notion of radial distance and results are presented on realistic models composed of hundreds of hierarchically globally deformed supershapes. An implicit equation with guaranteed differential properties is obtained by simple combinations of the primitives~ implicit representations using R-function theory. The surface corresponding to the zero-set of the implicit equation is efficiently and directly polygonized using the primitives,parametric forms. Moreover, hierarchical global deformations are considered to increase the range of shapes that can be modeled. The potential of the approach is illustrated by representing complex models composed of several hundreds of primitives inspired from CAD models of mechanical parts.展开更多
文摘This article presents the development and validation of the Superquadric Discrete Element Method(SuperDEM)for non-spherical particle simulation using a superquadric particle method in open-source CFD suite MFiX.A superquadric particle-particle contact algorithm with accelerating and stabilizing strategy was developed.A superquadric particle-arbitrary wall contact algorithm was developed,which enables the simulation in complex geometry.The solver was validated by comparing with experimental data generated in this study or available in the literature.Tests include cylinder contacting with a wall,static packing of M&M chocolate candies in a cylindrical container,static packing of cylinders in a cylindrical container,dynamic angle of repose of cylinders in a rotating drum,and discharging of chocolate candies from a hopper.Besides,MPI parallelization of the solver was implemented and the parallel performance of the solver using MPI was assessed through large-scale simulations of 1 million,10 million,and 100 million particles on up to 6800 cores,which demonstrates that the SuperDEM solver has great potential for industrial-scale systems simulation.
基金supported by the National Key Research and Development Program of China(grant Nos.2018YFA0605902,2016YFC1401505,and 2016YFC1402706)the National Natural Science Foundation of China(grant Nos.11872136 and 11772085)the China Postdoctoral Science Foundation(grant No.2020M670746).
文摘The research on the coupling method of non-spherical granular materials and fluids aims to predict the particle-fluid interaction in this study.A coupling method based on superquadric elements is developed to describe the interaction between non-spherical solid particles and fluids.The discrete element method(DEM)and the smoothed particle hydrodynamics(SPH)are adopted to simulate granular materials and fluids.The repulsive force model is adopted to calculate the coupling force and then a contact detection method is established for the interaction between the superquadric element and the fluid particle.The contact detection method captures the shape of superquadric element and calculates the distance from the fluid particle to the surface of superquadric element.Simulation cases focusing on the coupling force model,energy transfer,and large-scale calculations have been implemented to verify the validity of the proposed coupling method.The coupling force model accurately represents the water entry process of a spherical solid particle,and reasonably reflects the difference of solid particles with different shapes.In the water entry process of multiple solid particles,the total energy of the water entry process of multiple solid particles tends to be stable.The collapse process of the partially submerged granular column is simulated and analyzed under different parameters.Therefore,this coupling method is suitable to simulate fluid-particle systems containing solid particles with multiple shapes.
文摘In the previous work, an efficient method has been proposed to represent solid objects as multiple combinations of globally deformed supershapes. In this paper, this framework is applied with a new supershape implicit function that is based on the notion of radial distance and results are presented on realistic models composed of hundreds of hierarchically globally deformed supershapes. An implicit equation with guaranteed differential properties is obtained by simple combinations of the primitives~ implicit representations using R-function theory. The surface corresponding to the zero-set of the implicit equation is efficiently and directly polygonized using the primitives,parametric forms. Moreover, hierarchical global deformations are considered to increase the range of shapes that can be modeled. The potential of the approach is illustrated by representing complex models composed of several hundreds of primitives inspired from CAD models of mechanical parts.
