Two-dimensional Methane/Air Flame

Lange, de Hc Rick; Goey, de Lph Philip

doi:10.1080/00102209308907681

Cited by 22 publications

(7 citation statements)

References 3 publications

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“…Due to limited computational resources, and the complexity of detailed-chemistry combustion models, two-dimensional numerical flame simulations were restricted to singlestep chemistry mechanisms or highly reduced chemical mechanisms in the past. Lange and de Goey [20,21], and Mallens et al [22] presented numerical analysis of two-dimensional laminar, premixed methane-air flames with single-step chemistry, using adaptive grid refinement techniques. They investigated the impact of different burner geometries and the boundary conditions on the flame shape, and the flow-field.…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional simulations of steady perforated-plate stabilized premixed flames

Altay

Kedia²,

Speth

et al. 2010

Combustion Theory and Modelling

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The objective of this work is to examine the impact of the operating conditions and the perforated-plate design on the steady, lean premixed flame characteristics. We perform two-dimensional simulations of laminar flames using a reduced chemical kinetics mechanism for methane-air combustion, consisting of 20 species and 79 reactions. We solve the heat conduction problem within the plate, allowing heat exchange between the gas mixture and the solid plate. The physical model is based on a zero-Mach-number formulation of the axisymmetric compressible conservation equations. The results suggest that the flame consumption speed, the flame structure, and the flame surface area depend significantly on the equivalence ratio, mean inlet velocity, the distance between the perforated-plate holes and the plate thermal conductivity. In the case of an adiabatic plate, a conical flame is formed, anchored near the corner of the hole. When the heat exchange between the mixture and the plate is finite, the flame acquires a Gaussian shape stabilizing at a stand-off distance, that grows with the plate conductivity. The flame tip is negatively curved; i.e. concave with respect to the reactants. Downstream of the plate, the flame base is positively curved; i.e. convex with respect to the reactants, stabilizing above a stagnation region established between neighboring holes. As the plate's thermal conductivity increases, the heat flux to the plate decreases, lowering its top surface temperature. As the equivalence ratio increases, the flame moves closer to the plate, raising its temperature, and lowering the flame stand-off distance. As the mean inlet velocity increases, the flame stabilizes further downstream, the flame tip becomes sharper, hence raising the burning rate at that location. The curvature of the flame base depends on the distance between the neighboring holes; and the flame there is characterized by high concentration of intermediates, like carbon monoxide.

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Section: Introductionmentioning

confidence: 99%

Two-dimensional simulations of steady perforated-plate stabilized premixed flames

Altay

Kedia²,

Speth

et al. 2010

Combustion Theory and Modelling

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“…Although global mechanisms have been applied in many combustion simulations (see e.g. [6][7][8][9]), their lack of accuracy causes them to be useful for global studies only.…”

Section: Introductionmentioning

confidence: 99%

Modelling of Premixed Laminar Flames using Flamelet-Generated Manifolds

Oijen¹,

Goey²

2000

Combustion Science and Technology

690

264

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In order to reduce the computational cost of flame simulations, several methods have been developed during the last decades, which simplify the description of the reaction kinetics. Most of these methods are based on partial-equilibrium and steady-state assumptions, assuming that most chemical processes have a much smaller time scale than the flow time scale. These assumptions, however, give poor approximations in the 'colder' regions of a flame, where transport processes are also important.The method presented here, can be considered as a combination of two approaches to simplify flame calculations, i.e. a flamelet and a manifold approach. The method, to which we will refer as the Flamelet-Generated Manifold (FGM) method, shares the idea with flamelet approaches that a multi-dimensional flame may be considered as an ensemble of one-dimensional flames. The implementation, however, is typical for manifold methods: a low-dimensional manifold in composition space is constructed, and the thermo-chemical variables are stored in a database which can be used in subsequent flame simulations. In the FGM method a manifold is constructed using one-dimensional flamelets. Like in other manifold methods, the dimension of the manifold can be increased to satisfy a desired accuracy. Although the method can be applied to different kinds of flames, only laminar premixed flames are considered here.Since the major parts of convection and diffusion processes are present in one-dimensional flamelets, the FGM is more accurate in the 'colder' zones of premixed flames than methods based on local chemical equilibria. Therefore, less controlling variables are sufficient to represent the combustion process. Test results of one and two-dimensional premixed methane/air flames show that detailed computations are reproduced very well with a FGM consisting of only one progress variable apart from the enthalpy to account for energy losses.

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“…A stoichiometric methane/air mixture enters the computational domain with a parabolic velocity profile and a maximum velocity of 0.8 m/s. The stoichiometric methane/air flame on this burner is computed using the 2D flame code developed by de Lange and Mallens [11,14]. This code uses a one-step chemistry model; the stream function/vorticity formulation for the flow field and the combustion equations are discretized on an adaptive locally refined grid.…”

Section: Illustration: Flame Stretch In the Tip Of A Bunsen Flamementioning

confidence: 99%