Effect of particle-momentum on an isothermal flow-field inside a swirl combustor

TL;DR

This study uses CFD simulations to analyze how particles influence the flow inside a swirl combustor, revealing a downstream shift of the recirculation zone that affects flame stabilization.

Contribution

It introduces a simplified boundary condition approach to model flow rotation and investigates particle effects without combustion, providing new insights into flow dynamics.

Findings

Particles cause a downstream shift of the central recirculation zone

Flow rotation modeled with boundary conditions is effective

Particle size impacts flow structure and stability

Abstract

This paper investigates the impact of particles on isothermal flow inside a lab-scale swirl combustor for a fixed inlet swirl number of 0.67 using steady-state CFD simulations. The combustor geometry and baseline conditions, with no particles, are taken from Taamallah et al. [1], but with a simplification. In the present work, we provide rotation to the flow using velocity boundary condition, whereas in [1], a swirler is built into the geometry to achieve the same effect. Shear stress transport (SST) k-omega model, an eddy-viscosity based Reynolds averaged Navier-Stokes equation approach, is used for modelling turbulence. The comprehensive model is validated against the experimental axial-velocity data in [1]. Two simulations, one with 75 and another with 100 micron particles using Discrete particle model (DPM) were conducted to isolate the effect of particle motion on swirl-combustor flow without combustion. Their analysis shows significant downstream shift of central recirculation zone (CRZ). An effect that can significantly impact the stabilization of coal flame in pulverized particle reactors.