Continuum theory for dense gas-solid flow: A state-of-the-art review

Three-dimensional simulation of a solid–liquid flow by the DEM–SPH method

Applicability of a coarse-grained CFD–DEM model on dense medium cyclone

A Methodical Calibration Procedure for Discrete Element Models

Multiphase chemical reactors with characteristic multiscale structures are intrinsically discrete at the elemental scale. However, due to the lack of multiscale models and the limitation of computational capability, such reactors are traditionally treated as continua through straightforward averaging in engineering simulations or as completely discrete systems in theoretical studies. The continuum approach is advantageous in terms of the scale and speed of computation but does not always give good predictions, which is, in many cases, the strength of the discrete approach. On the other hand, however, the discrete approach is too computationally expensive for engineering applications. Developments in computing science and technologies and encouraging progress in multiscale modeling have enabled discrete simulations to be extended to engineering systems and represent a promising approach to virtual process engineering (VPE, or virtual reality in process engineering). In this review, we analyze this emerging trend and emphasize that multiscale discrete simulations (MSDS), that is, considering multiscale structures in discrete simulation through rational coarse-graining and coupling between discrete and continuum methods with the effect of mesoscale structures accounted in both cases, is an effective way forward, which can be complementary to the continuum approach that is being improved by multiscale modeling also. For this purpose, our review is not meant to be a complete summary to the literature on discrete simulation, but rather a demonstration of its feasibility for engineering applications. We therefore discuss the enabling methods and technologies for MSDS, taking granular and particle-fluid flows as typical examples in chemical engineering. We cover the spectrum of modeling, numerical methods, algorithms, software implementation and even hardware-software codesign. The structural consistency among these aspects is shown to be the pivot for the success of MSDS. We conclude that with these developments, MSDS could soon become, among others, a mainstream simulation approach in chemical engineering which enables VPE.

Discrete simulation of granular and particle-fluid flows: from fundamental study to engineering application

Verification and validation of a coarse grain model of the DEM in a bubbling fluidized bed

In nuclear engineering, fluid flows involving free surface were well studied, e.g., pipe thinning produced by liquid droplet impingement, and steam explosion triggered by molten metal immersed in water. The moving particle simulation (MPS) method was often used in past studies. In this method, the Poisson equation was solved to obtain the pressure field. Solving the Poisson equation becomes a dominant process. Reducing the time of calculation of the Poisson equation is important for using the CFD in the engineering fields. Thereat, we propose a new MPS method by which the pressure field is calculated explicitly. We call it the explicit (E-)MPS method. The E-MPS method was applied to a static water and dam break problem to show its adequacy. Besides, we compare the calculation time between the E-MPS method and traditional one.

Numerical Simulation of Three-Dimensional Free-Surface Flows with Explicit Moving Particle Simulation Method

In industrial arena, there are many solid-liquid two phase flow systems like mixing vessels, glass furnaces, solid-liquid separation equipments, etc. Numerical simulations are promising approach to understand the phenomena. Numerical analyses by the Eulerian-Lagrangian approach were performed in the past studies. The Eulerian-Lagrangian methods were applied to various solid-liquid flow systems without the free surfaces. On the other hand, numerical models which can treat the solid-liquid flows involving free surface were hardly developed so far. Hence, in the current study, we develop a Lagrangian-Lagrangian coupling methods to perform the fast simulation of the solid-liquid flows. The liquid phase were modeled by the Explicit Moving Particle Simulation (E-MPS) method. The E-MPS method can simulate the free surface flows easily. The DEM / E-MPS method was applied to a solid-liquid flow in a pipeline. The simulations were performed by changing the acoustic velocity. The simulation results, namely, the solid particle distribution, pressure and fluid velocity were compared in the present study. The DEM / E-MPS method is shown to make possible to perform the fast simulation by assuaging the acoustic velocity.

Numerical Simulation on a Solid-Liquid Flow in a Pipeline by a Lagrangian Approach

There are many products manufactured by powder compacting presses. In the past studies, the structural analyses of the product were performed by Finite Element Method (FEM). In these analyses, cavities which were occurred in the injection could not be taken into consideration. Namely, the analyses were performed under the assumption that the products were packed homogeneously. On the other side, the simulations of powder process were often performed by the Discrete Element Method (DEM). Accordingly, the structural analysis taking into account the particle condition could not be performed practically. Thereat, a new structure analytical method, which is referred to Finite Deformation theory based Particle Method (FD-PM), was developed to introduce the packing condition into the structural analyses. In this method, the particle location, i.e., random packing, could be simulated by the DEM. This location is used in the FD-PM as the calculation points. Numerical simulations of a cantilever oscillation were performed to investigate the adequacy of the FD-PM. Effects of the particle location on the structural analyses were investigated in this study. The oscillation cycle obtained from the simulations was compared with the theoretical one. The oscillation cycles were in good agreement between the simulations and the theoretical results. It is concluded that the FD-PM can simulate the oscillation of the cantilever composed of the randomly packed powder accurately.

https://www.jstage.jst.go.jp/article/sptj/48/7/48_7_464/_pdf

Shin Mizutani

Papers

Verification and validation of a coarse grain model of the DEM in a bubbling fluidized bed

Numerical Simulation of Three-Dimensional Free-Surface Flows with Explicit Moving Particle Simulation Method

Numerical Simulation on a Solid-Liquid Flow in a Pipeline by a Lagrangian Approach

Fundamental Study on a Structure Simulation for the Powder Products

WITHDRAWN: Numerical study on a solid–liquid flow by a Lagrangian–Lagrangian approach