Assessment of mesoscale solid stress in coarse-grid TFM simulation of Geldart A particles in all fluidization regimes

This study focused on assessing the effect of mesoscale solid stress in the coarse grid two-fluid model (TFM) simulation of gas-solid fluidized beds of Geldart Group A particles over a broad range of flow regimes, including bubbling, turbulent, fast, and pneumatic transport fluidization regimes. Particularly, the impact of mesoscale solid pressure, mesoscale solid viscosity, and mesoscale solid stress anisotropy were investigated by comparing six different coarse-grid TFM settings. Compared with the available experimental data, it is found that both the kinetic theory-based TFM with only drag correction and the filtered TFM can predict the flow behavior in all fluidization regimes. Mesoscale solid pressure and viscosity have the opposite impact on flow hydrodynamics; they compete and offset each other, which confirms the assumption employed in many previous studies that the mesoscale solid stress could be neglected in coarse-grid TFM simulation. Published 2018. This article is a U.S. Government work and is in the public domain in the USA. AIChE J, 64: 3565-3581, 2018