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This article was downloaded by Yale University On 12 May 2011 Access details Access Details subscription number 930573056 Publisher Taylor Francis Informa Ltd Registered in England and Wales Registered Number 1072954 Registered office Mortimer House 3741 Mortimer Street London W1T 3JH UK Combustion Theory and Modelling Publication details including instructions for authors and subscription information http www informaworld com smpp title content t713665226 Computational and experimental study of steady axisymmetric nonpremixed methane counterflow flames G Amantinia J H Frankb M D Smookea A Gomeza a Department of Mechanical Engineering Yale Center for Combustion Studies Yale University New Haven CT USA b Combustion Research Facility Sandia National Laboratories Livermore CA USA To cite this Article Amantini G Frank J H Smooke M D and Gomez A 2007 Computational and experimental study of steady axisymmetric non premixed methane counterflow flames Combustion Theory and Modelling 11 1 47 72 To link to this Article DOI 10 1080 13647830600792370 URL http dx doi org 10 1080 13647830600792370 PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use http www informaworld com terms and conditions of access pdf This article may be used for research teaching and private study purposes Any substantial or systematic reproduction re distribution re selling loan or sub licensing systematic supply or distribution in any form to anyone is expressly forbidden The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date The accuracy of any instructions formulae and drug doses should be independently verified with primary sources The publisher shall not be liable for any loss actions claims proceedings demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material Combustion Theory and Modelling Vol 11 No 1 February 2007 47 72 Computational and experimental study of steady axisymmetric non premixed methane counterflow flames G AMANTINI J H FRANK M D SMOOKE and A GOMEZ Department of Mechanical Engineering Yale Center for Combustion Studies Yale University New Haven CT 06520 USA Combustion Research Facility Sandia National Laboratories Livermore CA 94551 USA Downloaded By Yale University At 15 48 12 May 2011 Received 9 November 2005 in final form 8 May 2006 We investigated computationally and experimentally the structure of steady axisymmetric laminar methane enriched air diffusion flames Experimentally we imaged simultaneously single photon OH LIF and two photon CO LIF which also yielded the forward reaction rate RR of the reaction CO OH CO2 H In addition particle image velocimetry PIV was used to measure the velocity in the proximity of the fuel and oxidizer nozzles providing detailed boundary conditions for the simulations Computationally we solved implicitly the steady state equations in a modified vorticity velocity formulation on a non staggered non uniform grid We compared the results along the axis of symmetry from the two dimensional simulations with those from the one dimensional model and showed consistency between them The comparison between the experimental and computational data yielded excellent agreement for all measured quantities The field of these two dimensional flames can be roughly partitioned into two regions the region between the two reactant nozzles in which viscous and diffusive effects are confined to the mixing layer and to the nozzle walls where separation occurs and a radial development region which is initially confined by recirculation zones near the burner flanges Buoyancy is virtually irrelevant in the first region at all but the smallest and practically irrelevant strain rates Buoyancy on the other hand does play a role in the growth of the recirculation zones and in determining the flame location in the outermost region Keywords Counterflow Diffusion Flames Vorticity velocity formulation Notation A c p k div D DT g hk HR HRi k T NSPEC global strain rate specific heat capacity at constant pressure for the kth species divergence operator Brownian diffusivity thermal diffusivity of the mixture gravity acceleration total enthalpy for the kth species global heat release the heat release associated with the ith reaction forward rate constant of the elementary reaction CO OH CO2 H total number of species present in the chemical mechanism Corresponding author E mail alessandro gomez yale edu Combustion Theory and Modelling c 2007 Taylor Francis ISSN 1364 7830 print 1741 3559 online http www tandf co uk journals DOI 10 1080 13647830600792370 Downloaded By Yale University At 15 48 12 May 2011 48 r R RR T v vr vz Vk r Vk z VT Yk Z T HOT COLD st k G Amantini et al radius nozzle radius forward reaction rate of the elementary reaction CO OH CO2 H temperature velocity vector radial velocity axial velocity diffusion velocity in the radial direction for the kth species diffusion velocity in the axial direction for the kth species local particle drift velocity mass fraction of the kth species mixture fraction tangential momentum accommodation coefficient assumed to be unity dimensionless thermophoretic diffusion factor thermal conduction coefficient viscosity of the mixture momentum diffusivity of the gas mixture density of the mixture density of the mixture at the location where the temperature is maximum density of the mixture at the location where the temperature is minimum scalar dissipation rate scalar dissipation rate at the stoichiometric surface vorticity production rate for the kth species Superscripts FUEL OXID p fuel stream at the nozzle mouth oxidizer stream at the nozzle mouth particle 1 Introduction Most of the combustion work on two dimensional 2D counterflow flames focuses on the effects of the interaction of counterflow flames with a variety of time varying perturbations in the vicinity of the axis of symmetry Katta et al 1 investigated the interaction between different types of perturbations in hydrogen flames identifying various quenching patterns In Oh et al 2 the interaction between a single vortex and a methane counterflow flame was simulated Frouzakis et al 3 simulated 2D hydrogen flames and examined the sensitivity of such flames to the inlet boundary conditions Lee et al 4 and Frouzakis et al 5 studied the transition from a hydrogen diffusion flame to an edge flame capturing


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