An analysis of lean premixed ethylene-air flame stabilization over a backward facing step

Dash, P and Aditya, K and Kolla, H and Chen, JH (2023) An analysis of lean premixed ethylene-air flame stabilization over a backward facing step. In: AIAA Aviation and Aeronautics Forum and Exposition, AIAA AVIATION Forum 2023, 12 June 2023through 16 June 2023, San Diego, USA.

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Abstract

In practical combustors, flame stabilization is often achieved through the formation of recirculation zones as a result of their geometry. Cavity flameholders are used for flame stabilization in gas turbines and ram/scramjets. This study uses direct numerical simulation (DNS) to investigate flame stabilization and turbulent flame structure of premixed flames in a backward-facing step configuration. A lean mixture of ethylene and air, relevant to scramjet combustion, is introduced at the inlet of the combustor and evolved until a statistically stationary state is reached. Instantaneous and averaged fields of relevant quantities show a flame stabilized at the tip of the step, which is supported by a recirculation zone transporting vital radicals and enthalpy. Analysis of averages of reaction rates conditioned on progress variable shows a shift in the chemical pathway induced by the transported species from the recirculation zones, aiding flame stabilization. Additionally, it is observed that the shear layer generated eddies impact the preheat zone near the edge of the cavity, while their impact shifts toward higher progress variable values in the flame brush further downstream. © 2023, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

Item Type:	Conference Paper
Publication:	AIAA Aviation and Aeronautics Forum and Exposition, AIAA AVIATION Forum 2023
Publisher:	American Institute of Aeronautics and Astronautics Inc, AIAA
Additional Information:	The copyright for this article belongs to publisher
Keywords:	Combustion; Combustors; Facings; Reaction rates; Stabilization, Air flames; Backward facing-step; Backward- Facing step; Cavity flame holders; Direct-numerical-simulation; Flame stabilization; Lean premixed; Premixed Flame; Recirculation zones; Turbulent flame structure, Ethylene
Department/Centre:	Division of Interdisciplinary Sciences > Computational and Data Sciences
Date Deposited:	27 Aug 2024 09:16
Last Modified:	27 Aug 2024 09:16
URI:	http://eprints.iisc.ac.in/id/eprint/86065

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