A comparative study of flamelet and finite rate chemistry LES for an axisymmetric dump combustor

Abstract

Present-day demands on combustion equipment are increasing the need for improved understanding and prediction of turbulent combustion. Large eddy simulation (LES), in which the large-scale flow is resolved on the grid, leaving only the small-scale flow to be modeled, provides a natural framework for combustion simulations, as the transient nature of the flow is resolved. In most situations, however, the flame is thinner than the LES grid, and subgrid modeling is required to also handle the turbulence-chemistry interactions. Here, we examine the predictive capabilities of the flamelet LES models, such as the Flamelet Progress Variable LES (LES-FPV) models, and the finite rate chemistry LES models, such as the LES-Thickened Flame Model (LES-TFM), the partially stirred reactor model (LES-PaSR) and the Eddy Dissipation Concept (LES-EDC) model. These different combustion LES models are used here to study the reacting flow in an axisymmetric dump combustor at a Reynolds number of 55,800, the Damköhler number of 167 and a Karlowitz number of 0.15, placing the flame in the corrugated flame regime. The computational results are compared to experimental data of velocity and temperature to examine predictive capabilities of the different models.

Keywords:

• axisymmetric dump combustor
• large eddy simulation
• reacting turbulent flow
• subgrid turbulence-chemistry interaction models

Acknowledgement

This work was supported by the Swedish Armed Forces. The authors also thank A.M. Kempf, T.K.K. Ma and C.P.T. Groth for providing valuable comments on the study.