(213d) Numerical Study on a Gas-Solid Flow in an Arbitrary Shape Boundary Including Thin Plates

Gas-solid flow is widely encountered in the chemical engineering such as a fluidized bed. Coupled Discrete Element Method (DEM) - Computational Fluid Dynamics (CFD) method[1] has been often employed in various solid-fluid flow systems in industries so far and its adequacy was proven in the previous studies[2,3]. In DEM-CFD method, the size of CFD grid should be sufficiently larger than the size of DEM particle diameter according to the local volume average technique[4]. Although this technique provides a great advantage on the representation of the macroscopic behavior of a gas-solid flow, it is of great difficulty to calculate the solid-fluid multiphase flow systems including thin plates. This is because the thin wall cannot be represented by the existing DEM-CFD method due to the resolution.

In order to solve this problem, we developed a Refined Grid Model in DEM-CFD method, where the CFD grid size could be given independently of the particle diameter. This approach is indeed useful in many systems in industries. In this study, the Refined Grid Model was applied to the fluidized bed with a narrow gap channel to show the adequacy of the model. Fluidization conditions in a narrow channel were successfully performed by using this model, though the existing method could not simulate this system. Consequently, it is shown that this model makes it possible to perform a gas-solid flow in a powder system including thin plates.

Acknowledgement

This study was financially supported by JSPS KAKENHI (17J02825).

References

[1] Y. Tsuji, T. Kawaguchi, and T. Tanaka, “Discrete particle simulation of two-dimensional fluidized bed,” Powder Technol., vol. 77, no. 77, pp. 79–87, 1993.

[2] M. Sakai, H. Takahashi, C. C. Pain, J. P. Latham, and J. Xiang, “Study on a large-scale discrete element model for fine particles in a fluidized bed,” Adv. Powder Technol., vol. 23, no. 5, pp. 673–681, 2012.

[3] M. Sakai, M. Abe, Y. Shigeto, S. Mizutani, H. Takahashi, A. Viré, J. R. Percival, J. Xiang, and C. C. Pain, “Verification and validation of a coarse grain model of the DEM in a bubbling fluidized bed,” Chem. Eng. J., vol. 244, pp. 33–43, 2014.

[4] T. B. Anderson and R. O. Y. Jackson, “A Fluid Mechanical Description of Fluidized Beds,” Ind. Eng. Chem. Fundam., vol. 6, no. 4, pp. 527–539, 1967.