The role of unequal diffusivities in ignition and extinction fronts in strained mixing layers

Daou, J. and Liñán Martínez, Amable (1998). The role of unequal diffusivities in ignition and extinction fronts in strained mixing layers. "Combustion Theory and Modelling", v. 2 ; pp. 449-477. ISSN 1364-7830.

Description

Title: The role of unequal diffusivities in ignition and extinction fronts in strained mixing layers
Author/s:
  • Daou, J.
  • Liñán Martínez, Amable
Item Type: Article
Título de Revista/Publicación: Combustion Theory and Modelling
Date: 11 May 1998
ISSN: 1364-7830
Volume: 2
Subjects:
Faculty: E.T.S.I. Aeronáuticos (UPM)
Department: Motopropulsión y Termofluidodinámica [hasta 2014]
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

We have studied flame propagation in a strained mixing layer formed between a fuel stream and an oxidizer stream, which can have different initial temperatures. Allowing the Lewis numbers to deviate from unity, the problem is first formulated within the framework of a thermo-diffusive model and a single irreversible reaction. A compact formulation is then derived in the limit of large activation energy, and solved analytically for high values of the Damkohler number. Simple expressions describing the flame shape and its propagation velocity are obtained. In particular, it is found that the Lewis numbers affect the propagation of the triple flame in a way similar to that obtained in the studies of stretched premixed flames. For example, the flame curvature determined by the transverse enthalpy gradients in the frozen mixing layer leads to flame-front velocities which grow with decreasing values of the Lewis numbers. The analytical results are complemented by a numerical study which focuses on preferentialdiffusion effects on triple flames. The results cover, for different values of the fuel Lewis number, a wide range of values of the Damkohler number leading to propagation speeds which vary from positive values down to large negative values.

More information

Item ID: 1305
DC Identifier: http://oa.upm.es/1305/
OAI Identifier: oai:oa.upm.es:1305
Official URL: http://www.tandf.co.uk/journals/titles/13647830.asp
Deposited by: Biblioteca ETSI Aeronauticos
Deposited on: 18 Jan 2009
Last Modified: 20 Apr 2016 06:46
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