Numerical simulation of a laboratory-scale turbulent slot flame

We present three-dimensional, time-dependent simulations ofthe flowfield of a laboratory-scale slot burner. The simulations areperformed using an adaptive time-dependent low Mach number combustionalgorithm based on a second-order projection formulation that conservesboth species mass and total enthalpy. The methodology incorporatesdetailed chemical kinetics and a mixture model for differential speciesdiffusion. Methane chemistry and transport are modeled using the DRM-19mechanism along with its associated thermodynamics and transportdatabases. Adaptive mesh refinementdynamically resolves the flame andturbulent structures. Detailedcomparisons with experimental measurementsshow that the computational results provide a good prediction of theflame height, the shape of the time-averaged parabolic flame surfacearea, and the global consumption speed (the volume per second ofreactants consumed divided by the area of the time-averaged flame). Thethickness of the computed flamebrush increases in the streamwisedirection, and the flamesurface density profiles display the same generalshapes as the experiment. The structure of the simulated flame alsomatches the experiment; reaction layers are thin (typically thinner than1 mm) and the wavelengths of large wrinkles are 5--10 mm. Wrinklesamplify to become long fingers of reactants which burn through at a neckregion, forming isolated pockets of reactants. Thus both the simulatedflame and the experiment are in the "corrugated flameletregime."

[1]  Campbell D. Carter,et al.  Measured properties of turbulent premixed flames for model assessment, including burning velocities, stretch rates, and surface densities , 2005 .

[2]  Stephen B. Pope,et al.  Propagating surfaces in isotropic turbulence , 1992, Journal of Fluid Mechanics.

[3]  Friedrich Dinkelacker,et al.  Measurement of the resolved flame structure of turbulent premixed flames with constant reynolds number and varied stoichiometry , 1998 .

[4]  Joseph F. Grcar,et al.  Numerical simulation of premixed turbulent methane combustion , 2002 .

[5]  N. Swaminathan,et al.  Effects of mean flow divergence on turbulent scalar flux and local flame structure in premixed turbulent combustion , 2002 .

[6]  Christopher J. Rutland,et al.  Direct simulations of premixed turbulent flames with nonunity Lewis numbers , 1993 .

[7]  I. Shepherd,et al.  Flame front geometry in premixed turbulent flames , 1991 .

[8]  A. Leipertz,et al.  Lifted reaction zones in premixed turbulent bluff-body stabilized flames , 2002 .

[9]  V E Beckner,et al.  Numerical simulation of a laboratory-scale turbulent V-flame. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[10]  M S Day,et al.  Numerical simulation of laminar reacting flows with complex chemistry , 2000 .

[11]  Norbert Peters,et al.  Investigation of scalar mixing in the thin reaction zones regime using a simultaneous CH-LIF/Rayleigh laser technique , 1998 .

[12]  Luc Vervisch,et al.  Three facets of turbulent combustion modelling: DNS of premixed V-flame, LES of lifted nonpremixed flame and RANS of jet-flame , 2004 .

[13]  Charles J. Mueller,et al.  Vorticity generation and attenuation as vortices convect through a premixed flame , 1998 .

[14]  P. Colella,et al.  A Conservative Adaptive Projection Method for the Variable Density Incompressible Navier-Stokes Equations , 1998 .

[15]  Tianfeng Lu,et al.  Structure of a spatially developing turbulent lean methane–air Bunsen flame , 2007 .

[16]  R. Cheng,et al.  The influence of burner geometry on premixed turbulent flame propagation , 1991 .

[17]  P. Colella,et al.  Local adaptive mesh refinement for shock hydrodynamics , 1989 .

[18]  Stephen B. Pope,et al.  The curvature of material surfaces in isotropic turbulence , 1989 .

[19]  S. Sattler,et al.  Determination of three-dimensional flamelet orientation distributions in turbulent V-flames from two-dimensional image data , 2002 .

[20]  I. G. Shepherd,et al.  Premixed flame front structure in intense turbulence , 2002 .

[21]  I. Shepherd,et al.  Flame Front Curvature Distributions in a Turbulent Premixed Flame Zone , 1997 .