An Efficient Computational Model for Premixed Turbulent Combustion at High Reynolds Numbers Based on a Turbulent Flame Speed Closure

Zimont, V. L.; Polifke, Wolfgang; Bettelini, Marco; Weisenstein, Wolfgang

doi:10.1115/1.2818178

Cited by 188 publications

(57 citation statements)

References 11 publications

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“…Note also the following expression for the averaged progress variable (as amelets are thin, the probability to have 0 < c < 1 has been neglected): c = P b 1 + (1 P b ) 0 = P b (9) Therefore we can write: f W = const @c @x (10) where the constant is equal to u U t as can be shown by integrating equation (7) from 1 to +1.…”

Section: Introductionmentioning

confidence: 99%

Gradient, counter-gradient transport and their transition in turbulent premixed flames

Zimont¹,

Biagioli

2002

Combustion Theory and Modelling

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. In this case earlier work suggests that turbulent premixed ames have increasing ame brush width controlled in the model only by turbulence and independent from the counter-gradient transport phenomenon which has gasdynamics nature, and a turbulent ame speed which quickly adapts to a local equilibrium value, i.e. Intermediate Steady Propagation (ISP) ames. According to the present analysis transport in turbulent premixed ames is in fact composed by two contributions: real physical gradient turbulent di usion, which is responsible for the growth of ame brush thickness, and counter-gradient pressure-driven convective transport related to the di erential acceleration of burnt and unburnt gases subject to the average pressure variation across the turbulent ame. The novel gas dynamics model for the pressuredriven transport which is developed here, shows that in open turbulent premixed ames the overall transport may be of gradient or counter-gradient nature according to which of these two contributions is dominant and that along the ame a transformation from gradient to counter-gradient transport takes place. Reasonable agreement with the mentioned laboratory experimental data, strongly support the validity of the present modelling ideas. Finally, the model predicts existence of this phenomenon also in large-scale industrial burners at much higher Reynolds numbers.

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Section: Introductionmentioning

confidence: 99%

Gradient, counter-gradient transport and their transition in turbulent premixed flames

Zimont¹,

Biagioli

2002

Combustion Theory and Modelling

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“…The first was the well-known and experimentally validated correlation for the turbulent burning rate u t from Zimont [7,9]:…”

Section: Results For Isochoric Vesselmentioning

confidence: 99%

Comparison of Combustion Models and Assessment of Their Applicability to the Simulation of Premixed Turbulent Combustion in IC-Engines

Brandl

Pfitzner

Mooney

et al. 2005

Flow Turbulence Combust

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In order to simulate the turbulent combustion process occurring in spark-ignition (IC) engines, it is necessary to provide suitable and numerically economical models, the latter being particularly important in the application to industrial problems. Moreover, these models must deliver sufficiently accurate results for the unsteady operation of spark combustion engines, concerning variable geometries, temperatures, pressures and charge development in different configurations. In this work different turbulent combustion models for premixed hydrocarbon combustion are compared with respect to their ability to accurately predict the propagation of turbulent perfectly premixed flames.As a first configuration a cylinder of constant volume was studied. Transient calculations were used to simulate the propagation of the turbulent flame and to evaluate the resulting turbulent burning velocity. These calculations were performed for a perfect mixture of air and hydrocarbons at stoichiometric mixture and different initial conditions concerning pressure, temperature and turbulence intensity. As a second configuration a stationary turbulent bunsen-type flame with methane fuel was used to validate the turbulent combustion model of [Lindstedt and Vaos, Combust. Flame 116 (1999) 461] at different pressures. Calculated results were then compared to experimental data of [Kobayashi, Tamura, Maruta and Niioka. In: Proceedings of the 26th Symposium on Combustion, 1996, p. 389] and show excellent agreement for the turbulent burning velocity at several pressure levels using only a single set of model parameters.

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“…The Turbulent Flame Closure (TFC) mean reaction rate ρS c " ρ u U t |∇c|. ρ u and U t are the density of the unburnt gas and the turublent flame speed, respectively [14]. In Ewald's work, U t " U l p1`σ t q [15], where U l represents the laminar flame speed related to the equivalent ratio of fuel/air [16] and for the LES model: …”

Section: Combustion Modelmentioning

confidence: 99%

Scale Effect of Premixed Methane-Air Combustion in Confined Space Using LES Model

et al. 2015

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Gas explosion is the most hazardous incident occurring in underground airways. Computational Fluid Dynamics (CFD) techniques are sophisticated in simulating explosions in confined spaces; specifically, when testing large-scale gaseous explosions, such as methane explosions in underground mines. The dimensions of a confined space where explosions could occur vary significantly. Thus, the scale effect on explosion parameters is worth investigating. In this paper, the impact of scaling on explosion overpressures is investigated by employing two scaling factors: The Gas-fill Length Scaling Factor (FLSF) and the Hydraulic Diameter Scaling Factor (HDSF). The combinations of eight FLSFs and five HDSFs will cover a wide range of space dimensions where flammable gas could accumulate. Experiments were also conducted to evaluate the selected numerical models. The Large Eddy Simulation turbulence model was selected because it shows accuracy compared to the widely used Reynolds' averaged models for the scenarios investigated in the experiments. Three major conclusions can be drawn: (1) The overpressure increases with both FLSF and HDSF within the deflagration regime; (2) In an explosion duct with a length to diameter ratio greater than 54, detonation is more likely to be triggered for a stoichiometric methane/air mixture; (3) Overpressure increases as an increment hydraulic diameter of a geometry within deflagration regime. A relative error of 7% is found when predicting blast peak overpressure for the base case compared to the experiment; a good agreement for the wave arrival time is also achieved.

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An Efficient Computational Model for Premixed Turbulent Combustion at High Reynolds Numbers Based on a Turbulent Flame Speed Closure

Cited by 188 publications

References 11 publications

Gradient, counter-gradient transport and their transition in turbulent premixed flames

Gradient, counter-gradient transport and their transition in turbulent premixed flames

Comparison of Combustion Models and Assessment of Their Applicability to the Simulation of Premixed Turbulent Combustion in IC-Engines

Scale Effect of Premixed Methane-Air Combustion in Confined Space Using LES Model

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