(647g) Numerical Modeling on Gas-Solid Two-Phase Flow Including Thin Plates

Multiphase flows including granular media is widely encountered in the chemical engineering. Because the multiphase flows are regarded to be extremely complicated phenomena, introduction of numerical simulation techniques is desired for the better understanding. The Discrete Element Method coupled with Computational Fluid Dynamics method, so-called DEM-CFD method[1], has been often employed in various multiphase flow systems in industries so far. In the DEM-CFD method, the Local volume average technique[2] is introduced to evaluate the void fraction in each CFD grid. Although the advantages on the representation of the macroscopic behavior of multiphase flows has been proven in the previous studies[3]–[5], it is of great difficulty to calculate the multiphase flows including the thin plates.

To solve this problem, the new discretization technique in the DEM-CFD method is developed, namely the Refined grid model. In the Refined grid model, two different scales of grids are flexibly used: one is for the calculation of void fraction, drag force and buoyancy; the other is for the computation of the fluid equations. Using two kinds of grids, the multiphase flows including thin plates can be calculated in the staggered grids. In the current study, the adequacy of the Refined grid model is proven through the validation tests in the fluidized bed system. Besides, applicability of a scaling law model such as the coarse graining DEM to the Refined grid model is shown for the first time. Consequently, introduction of the numerical simulation techniques is drastically accelerated.

Acknowledgement

This study was financially supported by JSPS KAKENHI (17H02825), JSPS KAKENHI (17KK0110) and by Grant-in-Aid for JSPS Research Fellow from the Japan Society for the Promotion of Science (18J12267).

References

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