A Numerical Study of a Bluff-body Stabilized Diffusion Flame. Part 1. Influence of Turbulence Modeling and Boundary Conditions

Abstract

This is the first part of a paper on numerical prediction of a bluff-body stabilized turbulent diffusion flame of syngas and air. This part considers the influence of turbulence modeling and boundary conditions on the predictions. Part 2 investigates the effect of the turbulence-chemistry interaction model and the effect of finite-rate chemistry. Results based on the “standard” k-s model and a Reynolds-stress-equation (RSE) model are compared. Measurements are taken from the literature. The RSE model predicts results in better agreement with the measurements than the k-e model. The two models predict significantly different composition and temperature levels in the recirculation bubble created by the bluff body. The specification of the turbulence level in the fuel-jet has a substantial influence on the axial decay of mixture fraction. Grid-resolution studies show that a relatively coarse grid is capable of representing the present flow with sufficient accuracy to evaluate the various sub-models.

Keywords:

• Diffusion flame
• bluff-body
• recirculation
• turbulence models
• boundary conditions