Numerical simulation of effect of non-spherical particle shape and bed size on hydrodynamics of packed beds

Document Type: Research Paper

Authors

Department of Chemical Engineering, University of Mohaghegh Ardabili

Abstract

Fluid flow has a fundamental role in the performance of packed bed reactors. Some related issues, such as pressure drop, are strongly affected by porosity, so non-spherical particles are used in industry for enhancement or creation of the desired porosity. In this study, the effects of particle shape, size, and porosity of the bed on the hydrodynamics of packed beds are investigated with three non-spherical particles namely cylindrical, cone, and truncated cone in laminar and turbulent flow regimes (15 ≤ Re ≤ 2500) using computational fluid dynamics. According to results obtained from the simulations, it was observed that flow channelling occurs in the parts of the bed that are not well covered by particles, which is more near the wall. CFD simulations showed that the vortex flow around the cylindrical particles is more than the cone and truncated cone particles and are caused by increasing the pressure drop of fluid in the bed. It was also found that the particles creating less porosity in the bed, due to their shape, are caused by increasing the pressure drop of fluid. The numerical results showed good agreement with available empirical correlations in the literature.

Highlights

  • Flow channelling and vortex flow depend on particle shape, fluid velocity and bed porosity.
  • The pressure drop of fluid with truncated cone particles is lower than the cone and cylindrical particles.
  • Stationary points with cylindrical particles are more than the other particles.
  • Vortex flow increases the pressure drop of fluid.

Keywords


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