165018 20251204150239.0 doi 10.1016/j.proci.2014.06.026 sideral 91233 ART-2015-91233 eng Cifuentes, L. Universidad de Zaragoza Local volumetric dilatation rate and scalar geometries in a premixed methane-air turbulent jet flame 2015 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. Access copy available to the general public Unrestricted info:eu-repo/semantics/openAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 4.12 2015 ENERGY & FUELS 17 / 88 = 0.193 2015 Q1 T1 THERMODYNAMICS 5 / 57 = 0.088 2015 Q1 T1 ENGINEERING, MECHANICAL 4 / 131 = 0.031 2015 Q1 T1 ENGINEERING, CHEMICAL 16 / 135 = 0.119 2015 Q1 T1 2.515 2015 Chemical Engineering (miscellaneous) 2015 Q1 Physical and Theoretical Chemistry 2015 Q1 Mechanical Engineering 2015 Q1 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Dopazo, C. Universidad de Zaragoza (orcid)0000-0002-2267-8598 Martín, J. Universidad de Zaragoza (orcid)0000-0003-3908-0493 Domingo, P. Vervisch, L. 5001 600 Universidad de Zaragoza Dpto. Ciencia Tecnol.Mater.Fl. Área Mecánica de Fluidos 35, 2 (2015), 1295-1303 Proc. Combust. Inst. PROCEEDINGS OF THE COMBUSTION INSTITUTE 1540-7489 1791510 http://zaguan.unizar.es/record/165018/files/texto_completo.pdf Versión publicada 1795970 http://zaguan.unizar.es/record/165018/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:165018 articulos driver 2025-12-04-14:39:25 ARTICLE