Influence of strain fields on flame propagation

Mendes-Lopes, J. M. C.; Daneshyar, H.

doi:10.1016/0010-2180(85)90116-6

Cited by 24 publications

(4 citation statements)

References 14 publications

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“…As the flow approaches the wall, a decrease in axial velocity is accompanied by an increase in the radial velocity gradient. These results are consistent with that observed in previous studies of non-reacting and reacting stagnation flows (Mendes-Lopes & Daneshyar 1985;Rolon et al 1991). 2-D direct numerical simulations also show a linear radial velocity profile for over 60 % of the radial domain (Sone 2007).…”

Section: Appendix 1-d Modelling and Simulations Of Stagnation Flamessupporting

confidence: 81%

“…Law & Sung 2000). Experiments in jetwall stagnation flows show that such flames can be modelled as a dual axisymmetric stagnation-point flow, where the first stagnation flow is towards an apparent plane determined by the flame dilatation, and the second flow impinges on the stagnation surface (Mendes-Lopes & Daneshyar 1985). The experimental data of Mendes-Lopes and Daneshyar were compared to theoretical predictions using large activation energy asymptotic methods by Eteng, Ludford & Matalon (1986) and Kim & Matalon (1988), through fitting of the potential flow model to the strain rate just upstream of the flame and inferring the flame speed as a fit parameter.…”

Section: Introductionmentioning

confidence: 99%

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Experiments and modelling of premixed laminar stagnation flame hydrodynamics

2011

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The hydrodynamics of a reacting impinging laminar jet, or stagnation flame, is studied experimentally and modelled using large activation energy asymptotic models and numerical simulations. The jet-wall geometry yields a stable, steady flame and allows for precise measurement and specification of all boundary conditions on the flow. Laser diagnostic techniques are used to measure velocity and CH radical profiles. The axial velocity profile through a premixed stagnation flame is found to be independent of the nozzle-to-wall separation distance at a fixed nozzle pressure drop, in accord with results for non-reacting impinging laminar jet flows, and thus the strain rate in these flames is only a function of the pressure drop across the nozzle. The relative agreement between the numerical simulations and experiment using a particular combustion chemistry model is found to be insensitive to both the strain rate imposed on the flame and the relative amounts of oxygen and nitrogen in the premixed gas, when the velocity boundary conditions on the simulations are applied in a manner consistent with the formulation of the streamfunction hydrodynamic model. The analytical model predicts unburned, or reference, flame speeds that are slightly lower than the detailed numerical simulations in all cases and the observed dependence of this reference flame speed on strain rate is stronger than that predicted by the model. Experiment and simulation are in excellent agreement for near-stoichiometric methane-air flames, but deviations are observed for ethylene flames with several of the combustion models used. The discrepancies between simulation and experimental profiles are quantified in terms of differences between measured and predicted reference flame speeds, or position of the CH-profile maxima, which are shown to be directly correlated. The direct comparison of the measured and simulated reference flame speeds, S u , can be used to infer the difference between the predicted flame speed of the combustion model employed and the true laminar flame speed of the mixture, S 0 f , i.e. S u = S 0 f , consistent with recently proposed nonlinear extrapolation techniques.

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Section: Appendix 1-d Modelling and Simulations Of Stagnation Flamessupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Experiments and modelling of premixed laminar stagnation flame hydrodynamics

2011

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“…The seeder designed by Mendes-Lopez (1984) [10]. Fig.2, laser source (laser diode 532nm wave length) equipped with optics setup (cylindrical lens) to expend the laser beam into a plane (laser sheet) with 2mm thickness.…”

Section: Burning Velocity Measurement Systemmentioning

confidence: 99%

Burning Velocity Measurement of Biodiesel Fuel and Its Blends Using Particle Imaging Path Technique and Image Processing

Hasan

Mashkour

Mohammed

2018

JEASD

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In present investigation an air-blast atomizer was designed and developed for fuel atomization which is used in liquid fuel burner. The burning velocity was measured experimentally. The experiments have been performed for different liquid fuel types, air to liquid mass flow rates (ALR) and equivalence ratio (φ) to study the effects of these parameters on burning velocity (BV). The liquid fuels used during the tests are biodiesel (sunflower fatty acid methyl ester SME) and its blends (biodiesel-diesel Bx and biodiesel-kerosene Bkx) with three values of ALR (0.6, 0.8 and 1.0) for five values of φ (0.6, 0.8, 1.0, 1.2 and 1.4).The flames images were investigated for the region before the flame front by using imaging setup and using particle image path (PIP) with dispersion techniques. The image viewing regions is 366.6 mm 2 for determine the (BV). Matlab cod software has been used for a number of image processing techniques to identify and improve the detection of the path of particles movements. The results showed that the increasing of biodiesel ratio in blending with diesel and kerosene decreases the (BV), and the increasing of ALR increases the (BV) for all experiments fuels. Also the results showed that the agreement is good of this method of (BV) measurement with published studies.

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“…1(b), in previous studies, [4][5][6][7] the location of downstream maximum velocity (point a), the location of minimum velocity (point b, hereafter called the velocity method) and the location of upstream temperature boundary (1% temperature rise, point c, hereafter we called the temper-The chemical mechanism presented by Kee et al 15) is employed in this study. This chemistry includes 58 elementary reactions and 18 reacting species.…”

Section: Flame Thickness and Burning Velocitymentioning

confidence: 99%

Determination of Burning Velocity and Flammability Limit of Methane/Air Mixture Using Counterflow Flames

Guo²,

Maruta³

et al. 1999

Jpn. J. Appl. Phys.

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The burning velocity and the flammability limit of a methane/air mixture are investigated numerically using counterflow premixed flames. Two different methods, the minimum velocity method and the upstream temperature boundary method, for the determination of burning velocity are compared. The results show that the minimum velocity method fails when the chemical heat release is weak. A velocity gradient method is presented and examined. Furthermore, at low equivalence ratio, the results show that flame thickness increases exponentially with the decrease of stretch rate. This flame thickening results in a radiation extinction. An extrapolation of burning velocity to zero stretch is shown to be inaccurate. At a high equivalence ratio, it is found that two kinds of stable flames exist, normal flame and weak flame, with distinct burning velocities. A Gshaped curve showing the flammable regions is obtained by plotting the burning velocities at extinction limits as a function of equivalence ratio. The results indicate that a simple linear extrapolation of the extinction limits of stretched flames to zero stretch rate does not give the standard flammability limit.

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Influence of strain fields on flame propagation

Cited by 24 publications

References 14 publications

Experiments and modelling of premixed laminar stagnation flame hydrodynamics

Experiments and modelling of premixed laminar stagnation flame hydrodynamics

Burning Velocity Measurement of Biodiesel Fuel and Its Blends Using Particle Imaging Path Technique and Image Processing

Determination of Burning Velocity and Flammability Limit of Methane/Air Mixture Using Counterflow Flames

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