Effect of Inlet Boundary Conditions on Computational Fluid Dynamics (CFD) Simulations of Gas–Solid Flows in Risers

Abstract

Accurate computational fluid dynamics (CFD) simulation of gas-solid flows in circulating fluidized bed (CFB) risers requires appropriate specification of inlet boundary conditions, yet the influence of different inlet configurations on predicted flow patterns is not well established. This study systematically investigates the effect of inlet boundary conditions on Eulerian-Eulerian CFD simulations of gas-solid flows in risers using both 2D and 3D computational domains.

Three different inlet configurations were tested, varying how the solid and gas streams enter at the riser base. Results demonstrate that both the time-averaged axial velocity and solids volume fraction radial profiles are strong functions of the inlet kinetic energy profiles and gas-solid mixing patterns generated by each inlet configuration. The study found that an inlet configuration with solids entering axially from two-sided bottom inlets near the wall and gas entering from a bottom inlet at the centre, as well as full-scale 3D simulations, gave reasonable agreement with experimental observations. The findings highlight the critical importance of accurate inlet boundary condition specification in CFB riser simulations and provide guidance for practitioners conducting Eulerian-Eulerian CFD simulations of these systems.

@article{shah2012effect,
  title         = {Effect of Inlet Boundary Conditions on Computational Fluid Dynamics (CFD)
                  Simulations of Gas--Solid Flows in Risers},
  author        = {Shah, Milinkumar T and Utikar, Ranjeet P and Evans, Geoffrey M and Tade,
                  Moses O and Pareek, Vishnu K},
  year          = 2012,
  journal       = {Industrial \& Engineering Chemistry Research},
  publisher     = {American Chemical Society},
  volume        = 51,
  number        = 4,
  pages         = {1721--1728}
}