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Showing papers in "Combustion and Flame in 1979"


Journal ArticleDOI
TL;DR: In this paper, the authors applied matched asymptotic expansions to investigate the effects of heat losses on linear stability of a planar flame, which is governed by a one-step irreversible Arrhenius reaction.

372 citations


Journal ArticleDOI
TL;DR: In this paper, the steady-state flame spread over a thermally thin solid fuel is investigated, and qualitative agreement is obtained with experimental results in the near-extinction limit region.

183 citations


Journal ArticleDOI
TL;DR: In this article, the authors quantified the characteristic times associated with turbulent mixing, homogeneous chemical kinetics, liquid-droplet evaporation, and fuel injection for lean blowoff.

169 citations


Journal ArticleDOI
TL;DR: In this article, a complete family of concentration profiles for natural, positive flame ions has been measured mass spectrometrically below 55 amu (atomic mass units), sampled along the axis through the flame front.

155 citations


Journal ArticleDOI
TL;DR: In this paper, a model for the ignition of heterogeneous fuel-air mixtures that assumes that mixing rates and chemical kinetics are infinitely fast and that the sole criterion for successful ignition is an adequate concentration of fuel vapor in the ignition zone was described.

133 citations


Journal ArticleDOI
TL;DR: In this article, the authors studied the dynamic behavior of single carbon particles in a hot oxidizing ambient and derived analytical expressions for the rate of carbon mass loss showing the relative influences of the gas phase chemistry, the gas-phase convective and diffusive transport, and the heterogeneous reaction kinetics on the overall reaction rate.

131 citations


Journal ArticleDOI
TL;DR: In this article, the authors employed coherent anti-Stokes Raman spectroscopy (CARS) to map the temperature field with high spatial precision throughout a small, highly sooting, laminar propane diffusion flame.

128 citations


Journal ArticleDOI
TL;DR: In this article, computer-generated coherent anti-Stokes Raman spectroscopy (CARS) spectra, necessary for temperature and species concentration measurements in combustion environments, are presented.

108 citations


Journal ArticleDOI
TL;DR: In this article, a CO 2 laser with incident flux up to about 20 W/cm 2 under autoignition and piloted ignition in air was used for radiative ignition experiments on PMMA and red oak.

101 citations


Journal ArticleDOI
TL;DR: For a given stand-off distance of a laminar flame on a porous metal burner, it has been shown both experimentally and theoretically that there exists two solutions, a low speed flame and a high speed flame.

98 citations


Journal ArticleDOI
TL;DR: In this article, a least squares analysis of 24 runs covering the temperature range 1950-2770°K and total densities (2.37-8.91) × 10−6 mol cm−3 gave for k 1 (T) = 0.6 Z CH 4 M ( E 0 RT ) 4.2 exp ( (−E 0 RT) /4.2

Journal ArticleDOI
TL;DR: In this paper, laser-excited molecular fluorescence measurements of CH and CN were made in atmospheric-pressure, acetylene flames and the fluorescence intensity dependence on laser intensity was observed to depart from linearity as laser spectral intensities increased.

Journal ArticleDOI
TL;DR: In this article, the complex degradation chemistry of polyurethanes is reduced to the two major overall reactions of char formation and char oxidation, showing the smolder process to be oxygen-limited.

Journal ArticleDOI
TL;DR: In this article, a systematic numerical study of the structure of blast waves produced by constant-velocity and accelerating flames propagating away from the center of a spherical source region was conducted, showing that the maximum overpressure generated by such flames is no higher than that generated by a constant velocity flame that travels through the entire source region at the maximum velocity reached when the acceleration process ceases.

Journal ArticleDOI
TL;DR: In this article, a high-temperature Knudsen cell equipped with a gas inlet and modulated molecular-beam mass-spectrometric detection has been constructed to study the high temperature pyrolysis of model fuel compounds.

Journal ArticleDOI
TL;DR: In this paper, the effect of large but finite values of the two dominant characteristic numbers, a turbulence Reynolds number providing a measure of the intensity of the turbulence and a Damkohler number relating a turbulence time to a chemical time, was investigated for planar, oblique, and normal flames.

Journal ArticleDOI
TL;DR: In this article, an analysis of the critical conditions of thermal explosion based on bifurcation theory for nonlinear elliptic equations is presented, where it has been proved that the value of the Frank-Kamenetsky parameter δ equals the principal eigenvalue of the equation of heat conduction linearized about the point of bifury of the solution u(δ), which correspond to self-ignition and extinction points.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the formation of NO from fuel nitrogen (NH 3 ) in staged combustion, paying attention to NO, HCN, and NH 3 formation in the fuel-rich first stage combustion and the conversion of residual HCN and NH3 into NO in the second stage combustion.

Journal ArticleDOI
TL;DR: In this paper, a one-dimensional mathematical model for heat and mass balance has been proposed to elucidate the changes occurring in the temperature and density of the evaporation-pyrolysis zone in a naturally smoldering cigarette.

Journal ArticleDOI
TL;DR: In this article, a theoretical model for the propagation of flames over a solid fuel in a laminar forced oxidizing gas flow moving in the direction of flame propagation is developed, which makes use of a boundary-layer approximation to describe the flow and of an ignition surface temperature.

Journal ArticleDOI
TL;DR: In this article, a measurement of the ion density in the flame front of an atmospheric-pressure, premixed air-propane flame is presented based on the sheath-convection model of current collection by a Langmuir probe.

Journal ArticleDOI
TL;DR: In this paper, an experimental study of a laminar, two-dimensional inverted flame established in the wake of a thin plate inserted into the interior of the premixed gas stream was performed, and the effects of the radius of curvature of the very base of the flame on the blowoff limit were examined in detail.

Journal ArticleDOI
TL;DR: In this paper, the authors derived an expression for the unimolecular decomposition of ozone, k 1(M = O3) = 4.31 × 1014 exp (−22.2/RT) cm3 mole−1 sec−1, 300 ⩽ T ⌽ 3000°K.

Journal ArticleDOI
TL;DR: In this article, an analytical model of the radially averaged fluid mechanical properties of the fire whirl core, including the coupling between the fire-whirl core flow, the ground boundary layer, and the fuel heat transfer, was developed.


Journal ArticleDOI
TL;DR: In this paper, the authors measured the angular dissymmetry of the scattered light intensity, the dependence of the scattering intensity on incident light polarization, the light extinction at two different wavelengths, and the scattered intensity: extinction ratio.

Journal ArticleDOI
TL;DR: In this article, the structures and properties of a 60% hydrogen-40% air flame, both uninhibited and inhibited by the addition of 4% HBr to the unburnt gas, were computed using a reaction mechanism and rate coefficients previously proposed by Dixon-Lewis and Simpson.


Journal ArticleDOI
TL;DR: In this paper, the advantages of multichannel pulsed Raman spectroscopy as a diagnostic technique in gas-phase combustion systems are discussed, and the combination of two detection devices will further allow to determine the temperature and the concentration of the species.

Journal ArticleDOI
TL;DR: In this paper, a numerical analysis of the expected gas temperatures in compartment fires where the fuel consists of a pool of thermoplastic material is determined, and the dominant variable is the ratio of ventilation parameter to fuel area.