Turbulent Accelerating Combusting Flows with a Methane-Vitiated Air Flamelet Model

Fuente: arXiv
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Main Authors: Walsh, Sylvain L., Zhan, Lei, Mehring, Carsten, Liu, Feng, Sirignano, William A.
Format: Preprint
Published: 2024
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author Walsh, Sylvain L.
Zhan, Lei
Mehring, Carsten
Liu, Feng
Sirignano, William A.
author_facet Walsh, Sylvain L.
Zhan, Lei
Mehring, Carsten
Liu, Feng
Sirignano, William A.
contents This work presents a numerical study of a diffusion flame in a reacting, two-dimensional, turbulent, viscous, multi-component, compressible mixing layer subject to a large favorable streamwise pressure gradient. The boundary-layer equations are solved coupled with both the $k$-$ω$ and SST turbulence models. A compressible extension of the flamelet progress variable method has been proposed and tested for use with large eddy simulations or Reynolds-averaged Navier-Stokes analyses of the burning of methane in pure air and vitiated air; the latter being particularly relevant in turbine burner scenarios. Effects of the level of detail of the reaction mechanism on the sub-grid and resolved-scale computations are studied. A comparison is made with results obtained using a simplified one-step reaction. The numerical results employing the flamelet model with the more detailed reaction mechanism show faster chemistry, significantly reduced peak temperatures and stronger sensitivity to pressure. Vitiated air flames are found to be dominated by unstable solutions, resulting in a weak flame with substantially lower peak temperature and impeded development, struggling to persist without quenching.
format Preprint
id arxiv_https___arxiv_org_abs_2402_15123
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Turbulent Accelerating Combusting Flows with a Methane-Vitiated Air Flamelet Model
Walsh, Sylvain L.
Zhan, Lei
Mehring, Carsten
Liu, Feng
Sirignano, William A.
Fluid Dynamics
This work presents a numerical study of a diffusion flame in a reacting, two-dimensional, turbulent, viscous, multi-component, compressible mixing layer subject to a large favorable streamwise pressure gradient. The boundary-layer equations are solved coupled with both the $k$-$ω$ and SST turbulence models. A compressible extension of the flamelet progress variable method has been proposed and tested for use with large eddy simulations or Reynolds-averaged Navier-Stokes analyses of the burning of methane in pure air and vitiated air; the latter being particularly relevant in turbine burner scenarios. Effects of the level of detail of the reaction mechanism on the sub-grid and resolved-scale computations are studied. A comparison is made with results obtained using a simplified one-step reaction. The numerical results employing the flamelet model with the more detailed reaction mechanism show faster chemistry, significantly reduced peak temperatures and stronger sensitivity to pressure. Vitiated air flames are found to be dominated by unstable solutions, resulting in a weak flame with substantially lower peak temperature and impeded development, struggling to persist without quenching.
title Turbulent Accelerating Combusting Flows with a Methane-Vitiated Air Flamelet Model
topic Fluid Dynamics
url https://arxiv.org/abs/2402.15123