Keynote Talk: Development and Application of Flexible Eurelian-Lagrangian Method for Industrial Gas-Solid Flow Systems

The DEM-CFD method is well known as an Eulerian-Lagrangian method and has been employed to perform numerical simulations in industrial gas-solid flow systems. Modeling of arbitrary shape boundary becomes indispensable when the DEM-CFD method is applied to the industrial systems. This is because not the shape of the industrial systems always becomes simple. On top of that, efficient calculation technique is necessary so as to perform the simulations of industrial gas-solid flows because enormous number of calculated particles are used. In order to create the arbitrary shape calculation domain in the DEM-CFD simulation, the author’s group has developed an approach combining the sign distance functions and the immersed boundary method. This approach can create the arbitrary shape wall even if staggered grids are used. Very recently, the author’s group has developed a new flexible model by combining a scaling law model which is referred to as the coarse graining DEM with the wall boundary model. The coarse graining DEM makes it possible to perform a large-scale DEM-CFD simulations, where smaller number of calculated particles is used than actual one. This is because the coarse grain particle represents group of the original particles, where total energy agrees between them. In order to prove adequacy of the flexible model, several verification and validation tests has been performed in gas-solid systems such as fluidized bed and powder die-filling. The test results indicate that the flexible model can reproduce granular flow even in a complex shape domain. Consequently, adequacy of the new flexible model is proven.

This study was financially supported by JSPS KAKENHI (17H02825) and JSPS KAKENHI (17KK0110).