摘要:

The recent demonstration that radicals make a flame resistant to stretch has greatly enhanced our understanding of laminar flame behavior. Using chain-branchingJchain-breaking kinetics, proposed by Zeldovich and discussed by Linan, Seshadri and Peters have shown that (except in certain limits) the burning rate of the flame changes only in proportion to the (weak)stretch caused by slight flow divergence. Here we explore more fully the implications of their analysis showing, in particular, that the stretch decelerates the flame in all practical cases, as Karlovitz predicted.

ISSN:0010-2202    

DOI:10.1080/00102208508947006

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The phenomenon of quenching of cylindri cal convergent flames is considered in the framework of con stant density approximation. The parametric dependence of the effect is studied numerically using an adaptive finite element method. The numerical results are in good agreement with predictions of theoretical analysis from Frankel and Sivashin sky (1984).

ISSN:0010-2202    

DOI:10.1080/00102208508947007

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Conservation equations are numerically solved for the hot burned gas of methane-air with surrounding air with or without unburned methane to investigate the influence of the presence of unburned hydrocarbon in the surrounding air and of the surrounding gas temperature on the formation of N02 in the mixing region of hot burned gases with surrounding cool air. The spatial distributions of temperature and species concentrations in the gas mixture were predicted in laminar flow field at atmospheric pressure. In the mixing region, the presence of unburned methane in the surrounding air is found to promote the conversion of NO to N02and its conversion ratio N02/NOxincreases with increa se in the amount of unburned methane. The N02formation in the mixing region is suppressed with increase in the temperature of surrounding air with or without unburned methane.

ISSN:0010-2202    

DOI:10.1080/00102208508947008

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A model is derived from the full equations governing combustion, in which a flame, located near a flarneholder, is viewed as a three-dimensional surface of discontinuity in the flow field. Jump conditions for the fluid variables, as well as an expression for the flame speed, are obtained from an asymptotic analysis of the detailed structure of the flame. The model is applied to investigate the linear stability of steady plane flames in the presence of heat loss to the flameholder. Stable flames exist only if the inflow velocity is sufficiently lower than the adiabatic flame speed, and then only in a certain regime of the parameters: Lewis number, heat release, and heat loss.

ISSN:0010-2202    

DOI:10.1080/00102208508947009

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The behavior of boron oxide drops was studied in the post flame region of a flat-flame burner. Individual particles were supported on a probe and rapidly could be placed in the gas environment. Measurements were made of the variation of particle size and temperature with time. Burner operating conditions were varied to give fuel equivalence ratios in the range 0.3–0.7 and gas temperatures in the range 1500–1975 K at atmospheric pressure. Flame environments both with and without water vapor present were con sidered. Results show that boron oxide gasification is a relatively slow process with 1000 μm initial diameter drop lifetimes ranging from two minutes to two hours. The presence of water vapor speeds gasification, as suggested by King, and probably accounts for the shorter ignition delay s observed for the oxidation of bo ron particles in wet en vironments. Application of a diffusion-limited equilibrium model provided excellent agreement with oxide drop-life histories at all conditions except for the low-temperature (Tp< 1300 K) wet environment. In th is case, results of a partial-equilibrium analysis suggest chemical kinetics limit gasification rates.

ISSN:0010-2202    

DOI:10.1080/00102208508947010

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0010-2202    

DOI:10.1080/00102208508947011

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The present work is devoted to the descr iption of a device which allows the detonation of gaseous explosive mixtures at initial pressures up to 80 bars. The detonation velocities are measured on two sections of a 55-mm i.d. and 4-m-long tube. The first results show that the detonation initiated with a Briska detonator becomes rap idly steady after a distance lower than 90 cm from the point of ignition. Experimental values of the detonation velocity are presented for a C2H4-air mixture. These data are compared to results of calculation using a thermochemical code based on a virial Equation of State. The discrepancy never exceeds 1 percent.

ISSN:0010-2202    

DOI:10.1080/00102208508947012

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Solutions containing one14C-labeled compound and a second unlabeled compound were burned as diffusion flames. Experiments were performed with [14C] methanol, [1-14C] ethanol, [1-14C] n-octanol, [2-14C] acetone, [U-14C] cyclohexane, and [methyl-14C] toluene.14C-labeled acetone, ethanol, n-octanol, cyclohexane, and toluene were also burned individually. Soot was collected from flame product gases on glass-fiber filters. Comparison of soot14C-activity with that of the liquid fuel establishes fuel-to-soot conversion ratios for chemically-inequivalent carbon atoms. Experiemtnal data, analysed in terms of a probabilistic model, indicate that (a) an acetone methyl carbon is 100±10 times more likely to undergo fuel-to-soot conversion than an acetone carbonyl carbon; (b) aliphatic carbon: hydroxyl carbon fuel-to-soot conversion ratios are 2.0±0.2 and 2.3±0.3 for ethanol and n-octanol; (c) aromatic: aliphatic conversion ratios range between 1.3:1 and 2.5:1 for a variety of toluene binary solutions.

ISSN:0010-2202    

DOI:10.1080/00102208508947013

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0010-2202    

DOI:10.1080/00102208508947014

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0010-2202    

DOI:10.1080/00102208508947015

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor