摘要:

A modelling study of combustion inhibition in an idealized well-stirred reactor utilizing H2/O2/Ar mixtures as the reactants is presented and discussed. The effect of two chemical inhibitors, HCl and HBr, on the combustion process has been investigated at pressures of 0.01 and l.0 atmosphere over a range of equivalence ratios of 0.5 to 1.5 and inhibitor concentrations of 0 to 10 percent. Inhibitor effectiveness was determined by the competition between the radical scavenging ability of an inhibitor and the exothermicity of the scavenging reactions. For all cases considered HBr was more effective in scavenging active radicals than HCl. At 0.01 atmospheres, HCl was a more effective inhibitor in lean and stoichiometric mixtures while HBr was more effective for rich mixtures at 0.01 atmosphere and for all atmospheric pressure mixtures.

ISSN:0010-2202    

DOI:10.1080/00102208208923593

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The effects of non-unity Lewis numbers of fuel and oxidizer on the structure of diffusion flames are studied for a variety of flow configurations. By using a generalized formation for the three-dimensional flame-sheet combustion, it is shown that the flame-sheet temperature is increased/decreased with decreasing/increasing Lewis number of either reactant, and that blowing reduces/aggravates these non-unity Lewis number effects if it is parallel/opposing the direction of diffusion. Ignition and extinction analyses are also conducted, yielding explicit criteria governing the occurrence of these events. The falsification of empirically-determined activation energy with the unity Lewis number assumption is emphasized.

ISSN:0010-2202    

DOI:10.1080/00102208208923594

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The macroscopic transport equations governing the axisymmetric flow, mixing, and reaction of NH3with high temperature combustion products containing NO and O2have been solved numerically and compared to published experimental data for the same geometry. The elementary chemical kinetic mechanism used was based on an earlier model developed from plug flow experimental data. The results show generally good agreement between the calculations and experimental data. Spatial distributions of the contributions of individual elementary reactions to the overall reaction and of the contribution of diffusion processes and reaction processes to the structure of the reaction zone were evaluated. Additional model calculations were used to evaluate the effect of the rate of mixing of NH3with combustion products on NO reduction efficiency. Finite rates of mixing were found to have little effect on the temperature dependence of the NO reduction. However, at high temperature the oxidation to form NO was found to be inhibited by finite mixing rates.

ISSN:0010-2202    

DOI:10.1080/00102208208923595

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

“Onion peeling“, Abel transformation and Fourier convolution reconstruction techniques have been compared in terms of their ability to accurately reconstruct axisymmetric, non-reacting and reacting flow fields from computer simulated absorption measurements. The effect of the shape of the flow field, the number of measurements and the measurement error on reconstruction accuracy are studied. The reconstruction techniques are shown to yield different results from the same set of absorption data. The reasons for this are discussed. Analysis of the frequency spectrum of the data is shown to be very useful for estimating the number of measurements required for adequate sampling and for determining the cut-off frequency for selectively filtering high frequency noise components from measurements with random error. The effect of measurement error on the reacting flow reconstructions was found to be greatest in the temperature profiles.

ISSN:0010-2202    

DOI:10.1080/00102208208923596

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The reaction of nitromethane over NiO/alumina and Cr2O3/alumina catalysts was examined to determine the feasibility of developing a nitromethane based monopropellant system. The kinetics of nitromethane decomposition over those two catalysts were found to be adequately represented by Langmuir-Hinshelwood kinetics over the conditionsT= 100-300°C,P= 1-60 torr. Nitromethane decomposition caused catalyst deactivation by carbon deposition due to the fuel rich nature of nitromethane. It is suggested that nitromethane be mixed with an oxidant rich material to eliminate the problem of carbon deposition to develop a functional monopropellant system.

ISSN:0010-2202    

DOI:10.1080/00102208208923597

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

This paper presents a linear analysis of the hydrodynamic stablity of the plane flame front of a premixed laminar flame. The technique of outer and inner asymptotic expansions is used to calculate the next approximation to the classical long-wave Landau limit. The resulting correction turns out to be independent of the Prandtl number. This implies that, although diffusivity, conductivity and viscosity in gases are of the same order of magnitude, viscosity exerts a secondary influence in comparison with diffusivity and conductivity.

ISSN:0010-2202    

DOI:10.1080/00102208208923598

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A speculative, phenomenological model is formulated for the time-varying intensity and spread rate of a free-burning fire under the influence of nonsteady wind. The model is linearized by approximations and explicit solutions derived for the amplitude response of spread rate and intensity as a function of the frequency of windspeed variations. Stylistic descriptions of typical wildland fuels are used to generate examples. The responses predicted for these fuels are intuitively satisfactory. The only directly observable feature of fire behavior predicted by the model is an inferred periodicity for the issuance of billows of smoke as the fire alternately races and pauses in response to the low-frequency variations (<0.05 Hz) in windspeed.

ISSN:0010-2202    

DOI:10.1080/00102208208923599

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Analysis is made of the rotational and potential fields in an open premixed turbulent flame to deduce the relative strengths of these fluctuating fields. The potential field, loosely described as the acoustic field, is found to be as strong as the rotational field for sufficiently high heat release, in accordance with prior estimates for ducted flames. The potential field decouples from the vortical field enabling separate calculations of correlations involving the potential field which are of importance in turbulence stress equations. For the case of a plane flame orthogonal to the oncoming stream and in the limit of a weak potential field these results are used to form a model for the velocity-pressure gradient correlation. The model differs from and is believed superior to others reported in the literature.

ISSN:0010-2202    

DOI:10.1080/00102208208923600

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The equations of one-dimensional laminar flame propagation were numerically resolved to study the formation of NO2in the premixed methane-air and hydrogen-air flames at atmospheric pressure. The results show the formation of NO2peak in the flame region prior to the rapid formation of NO (say prompt NO) in the methane flame, whereas they do not show the formation of NO2peak in the hydrogen flame in which NO is not formed rapidly. The formation of NO2in the flame is controlled by the concentration and formation rate of prompt NO as well as the concentrations of HO2and H, mainly through the reaction of NO + HO2→NO2+ H.NO2is consumed mainly through the reaction of NO2+ H→NO +OH coincidently with the rapid appearance of NO.

ISSN:0010-2202    

DOI:10.1080/00102208208923601

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0010-2202    

DOI:10.1080/00102208208923602

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor