摘要:

The study of the structure of turbulent flames, the basis of which is summarized in the first part of this article, requires numerous experimental results. To do so, we made an experimental study, of which we present only a qualitative aspect in the second part of this article. These experimental proceedings used a tomographic laser method which enabled us to visualize local and instantaneous isothermal lines within seeded premixed or diffusion flames obtained by means of a bunsen burner. To establish the influence of the turbulence on the structure of the flame, we used different speeds up to 8 m/s.

ISSN:0010-2202    

DOI:10.1080/00102208608923888

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The classical problem of the ignition and flame generation of combustible premixed gases by a hot flat plate is analyzed by asymptotic techniques for moderate values of the Zeldovich numbers. For temperatures of the plate smaller than the adiabatic flame temperature it was found that the corrections to the zeroth-order solution (Zeldovich approximation) are very important for finite Zeldovich numbers. The asymptotic analysis was carried out with the inclusion of reactant consumption showing different responses depending if the reactant consumption parameter is larger or smaller than a critical one. For temperatures of the plate larger than the adiabatic flame temperatures (that is, the reactant consumption parameter larger than the critical one), the ignition is not characterized by a thermal runaway and a smooth transition from frozen to equilibrium flow is obtained. The evolution towards the premixed flame formation is analyzed and the flame position and flame temperature are obtained.

ISSN:0010-2202    

DOI:10.1080/00102208608923889

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The ignition characteristics of a plasma jet, a commercial jet and a spark gap igniter have been studied in a combustion bomb at sub-atmospheric pressures. It was found that the plasma jet igniter promoted increased flame growth, particularly for stoichiometric mixtures and extended the flammability limits to both richer and leaner mixture strengths. The rapid formation of ignition kernels large enough to be self-sustaining at low pressures may be of importance in the restarting of jet engines at high altitudes.

ISSN:0010-2202    

DOI:10.1080/00102208608923890

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The infrared absorption of hydrocarbons is important in the determination of the effect of thermal blockage on the ignition and combustion of condensed fuels. Low-resolution spectral absorptivity data for propylene in the region from 2 to 15 μ are presented for temperatures between 290 and 830 K and pressures between 0.05 and 2 atm. The data have been used in conjunction with the general statistical narrow-band model and Edwards' exponential wideband model to define the spectral absorption characteristics of the gas. The wide-band model is used to calculate the Planck mean absorption coefficient and total emissivity, which are presented in graphical form.

ISSN:0010-2202    

DOI:10.1080/00102208608923891

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

An Australian bituminous coal was burnt in a laboratory drop-tube combustor at 1400, 1500 and 1600°C to determine the effect of p.f. properties and combustion temperature on the character and particle size of the flyash. The experiments showed that the mass mean particle size of the flyash was approximately proportional to that of the p.f., and almost independent of combustion temperature. In contrast, the proportion of fine ash (< 10 μ) was independent of p.f. size but increased markedly with increased combustion temperature. The upper size of the ash was determined by unburnt char for the 175 μm and 240 μm p.f. and by the mineral matter for the 29 μm p.f. Cenosphere formation increased with combustion temperature and dominated the ash formed at 1600°C. The work emphasises the need for more detailed p.f. analysis during laboratory and pilot-scale combustion studies into flyash formation and related phenomena such a's fouling, filtration and precipitability. Additional research is required to quantify cenosphere formation and its influence on the formation of fine flyash.

ISSN:0010-2202    

DOI:10.1080/00102208608923892

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

New concepts are addressed for predicting the flame spread on materials from laboratory measurements. It focuses on heat transfer which precipitates and precedes upward flame spread on a vertical surface. Six materials have been featured in this study as well as in past related studies. Their flame spread properties are presented. In this particular study heat transfer and flame height results are presented for wall samples burned at varying levels of external irradiance. Also complementary results are presented for methane line burner wall fires. An approximate theoretical analysis is included to serve as a guide to identifying the important variables and their relationship for correlation purposes. Experimental results yield flame height proportional to energy release rate to the 2/3 power, and wall heat flux distributions are roughly correlated in terms of distance divided by flame height. These correlations appear to at least hold for the scale of these experiments: flame heights of 0.3 to 1.47thinsp;m.

ISSN:0010-2202    

DOI:10.1080/00102208608923893

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor