Finding the markstein number using the measurements of expanding spherical laminar flames

Karpov, V. P.; Lipatnikov, Andrei; Wolański, P.

doi:10.1016/s0010-2180(96)00166-6

Cited by 71 publications

(35 citation statements)

References 18 publications

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“…Measured (points) and calculated (line) unstretched laminar burning velocities for hydrogen-air flames at standard temperature and pressure. Crosses: [90]; squares: [89]; open diamonds: [13,14]; solid diamonds: [19]; circles: [91]; triangles: [92]; stars: [93].…”

Section: Hydrogen Oxidation In a Flow Reactormentioning

confidence: 99%

Remaining uncertainties in the kinetic mechanism of hydrogen combustion

Konnov

2008

Combustion and Flame

306

293

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Section: Hydrogen Oxidation In a Flow Reactormentioning

confidence: 99%

Remaining uncertainties in the kinetic mechanism of hydrogen combustion

Konnov

2008

Combustion and Flame

306

293

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“…Turbulent flame extinction is to be expected when the Karlovitz number [22] Ka = 0.157 u u n 2 Re −1/2 (15) tends to unity [4]. For 0.346DTBP + 1.0N 2 , the measured quenching limit corresponds to the much lower value Ka ≈ 0.35.…”

Section: Discussionmentioning

confidence: 99%

“…The mass burning rate is defined unambiguously, whereas the displacement speed depends both on a particular position within the flame brush and on flame geometry. Spherically growing flames are subject to a variable stretch rate caused by both the hydrodynamic stretch and the changing curvature of their surface, the response to which is characterized by the Markstein length L b [15]. With an assumption of an infinitely thin flame front, the total stretch rate immediately ahead of a spherical flame is…”

Section: Apparatus Experimental Procedure and Data Interpretationmentioning

confidence: 99%

Experimental studies of the role of chemical kinetics in turbulent flames

Burluka

Griffiths

Liu

et al. 2009

Combust Explos Shock Waves

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Flames of di-t-butyl-peroxide (DTBP) decomposition in a 0.376DTBP + 1.0N 2 mixture are studied in laminar and turbulent media. The observed values of unstretched laminar burning velocity are in reasonable agreement with the value obtained from the Zel'dovich-Semenov-Frank-Kamenetsky theory. Turbulent explosions in this particular mixture are characterized by a number of features that are believed to be common for all developing turbulent flames and have relevance to spark-ignition engine combustion of lean mixtures. Flame propagation is unsteady and is characterized by a mass burning rate that increases in time. The rate of the flame acceleration varies from one explosion to another. If the burning rate is related to the average flame radius, however, it exhibits much smaller variations. This phenomenon bears a striking resemblance to cycle-to-cycle variations in a spark-ignition engine. Comparisons of the present results with mixtures of significantly different composition, chemical kinetics, and exothermicity, but with similar laminar flame speed and Lewis number show that the data obtained in closed-volume explosions are in good agreement if the unsteady character of the flame is taken into account. The differences in details of the kinetic mechanisms and thermochemistry appear to be responsible for the flame behaviour only near the limit of extinction by turbulence.

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“…There are various methods found in the literature for relating stretch rate and stretched flame speeds such that the fundamental mixture parameters, the unstretched laminar burning velocity, s u o , and Markstein length, L u , can be extracted as described in Refs. [27,[31][32][33][34]. The present study uses a commonly employed relation, first postulated by Markstein [31]: …”

Section: Effect Of Cylindrical Confinement On Laminar Flame Speed Meamentioning

confidence: 99%

Reduced and Validated Kinetic Mechanisms for Hydrogen-CO-sir Combustion in Gas Turbines

Ju¹,

Dryer²

2009

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Rigorous experimental, theoretical, and numerical investigation of various issues relevant to the development of reduced, validated kinetic mechanisms for synthetic gas combustion in gas turbines was carried out -including the construction of new radiation models for combusting flows, improvement of flame speed measurement techniques, measurements and chemical kinetic analysis of H 2 /CO/CO 2 /O 2 /diluent mixtures, revision of the H 2 /O 2 kinetic model to improve flame speed prediction capabilities, and development of a multi-time scale algorithm to improve computational efficiency in reacting flow simulations. Executive SummaryRigorous experimental, theoretical, and numerical investigation of various issues relevant to the development of reduced, validated kinetic mechanisms for synthetic gas combustion in gas turbines was carried out -including the construction of new radiation models for combusting flows, improvement of flame speed measurement techniques, measurements and chemical kinetic analysis of H 2 /CO/CO 2 /O 2 /diluent mixtures, revision of the H 2 /O 2 kinetic model to improve flame speed prediction capabilities, and development of a multi-time scale algorithm to improve computational efficiency in reacting flow simulations.An accurate spectral dependent radiation model is developed to predict flame speed and flammability of H 2 /CO/CO 2 /H 2 O/Air mixtures. The results showed that radiation reabsorption significantly extended the flammability limits. It was also demonstrated that accurate prediction of coal syngas flammability is not possible without appropriate consideration of radiation absorption by CO 2 and H 2 O.Methodologies to improve flame speed measurement were developed by experimental and theoretical investigation of the effect of non-spherical (i.e. cylindrical) bomb geometry on the evolution of outwardly propagating flames and the determination of laminar flame speeds. The cylindrical chamber boundary modifies the propagation rate through the interaction of the wall with the flow induced by thermal expansion across the flame (even with constant pressure), which leads to significant distortion of the flame surface for large flame radii. It was determined that these departures from the unconfined case, especially the resulting non-zero burned gas velocities, can lead to significant errors in flame speeds calculated using the conventional assumptions, especially for large flame sizes.The methodology to estimate the effect of nonzero burned gas velocities is applied to correct the flame speed for non-zero burned gas speeds, in order to extend the range of flame radii useful for flame speed measurements. Under the proposed scaling, the burned gas speed can be well approximated as a function of only flame radius for a given chamber geometry -i.e. the correction function need only be determined once for an apparatus and then it can be used for any mixture. Results indicate that the flow correction can be used to extract flame speeds for flame radii up to 0.5 times the wall radius wi...

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Finding the markstein number using the measurements of expanding spherical laminar flames

Cited by 71 publications

References 18 publications

Remaining uncertainties in the kinetic mechanism of hydrogen combustion

Remaining uncertainties in the kinetic mechanism of hydrogen combustion

Experimental studies of the role of chemical kinetics in turbulent flames

Reduced and Validated Kinetic Mechanisms for Hydrogen-CO-sir Combustion in Gas Turbines

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