Local volumetric dilatation rate and scalar geometries in a premixed methane-air turbulent jet flame

Cifuentes, L. (Universidad de Zaragoza) ; Dopazo, C. (Universidad de Zaragoza) ; Martín, J. (Universidad de Zaragoza) ; Domingo, P. ; Vervisch, L.

Resumen: The local volumetric dilatation rate, namely, the rate of change of an infinitesimal fluid volume per unit volume, [fórmula], is an important variable particularly in flows with heat release. Its tangential and normal strain rate components,[fórmula] and [fórmula] , respectively, account for stretching and partially for separation of iso-scalar surfaces. A three-dimensional direct numerical simulation (DNS) of a turbulent premixed methane–air flame in a piloted Bunsen burner configuration has been performed by solving the full conservation equations for mass, momentum, energy and chemical species using tabulated chemistry. Results for the volumetric dilatation rate as a function of the iso-scalar surface geometry, characterized by the mean and Gauss curvatures, [fórmula] and [fórmula] , are obtained in several zones (reactants, preheat, reacting and products) of the computational domain. Flat iso-scalar surfaces are the most likely geometries in agreement with previous DNS. The relationship between density and a reaction progress variable, under a low Mach number flamelet assumption, leads to an expression for [fórmula] with contributions from progress variable source and molecular diffusion budget, with a significant contribution from the latter; this approximate expression for the volumetric dilatation rate is studied with DNS results. The joint pdf of [fórmula] and[fórmula] confirms that the line [fórmula] separates mostly expansive flow regions from compressive zones.

Idioma: Inglés

DOI: 10.1016/j.proci.2014.06.026

Año: 2015

Publicado en: PROCEEDINGS OF THE COMBUSTION INSTITUTE 35, 2 (2015), 1295-1303
ISSN: 1540-7489

Factor impacto JCR: 4.12 (2015)

Categ. JCR: ENERGY & FUELS rank: 17 / 88 = 0.193 (2015) - Q1 - T1
Categ. JCR: THERMODYNAMICS rank: 5 / 57 = 0.088 (2015) - Q1 - T1
Categ. JCR: ENGINEERING, MECHANICAL rank: 4 / 131 = 0.031 (2015) - Q1 - T1
Categ. JCR: ENGINEERING, CHEMICAL rank: 16 / 135 = 0.119 (2015) - Q1 - T1

Factor impacto SCIMAGO: 2.515 - Chemical Engineering (miscellaneous) (Q1) - Physical and Theoretical Chemistry (Q1) - Mechanical Engineering (Q1)

Tipo y forma: Artículo (Versión definitiva)

Área (Departamento): Área Mecánica de Fluidos (Dpto. Ciencia Tecnol.Mater.Fl.)