摘要:

The propene low-temperature combustion process has been studied by means of the CSTR experimental technique. Dynamic behaviour with varying feed ratios and residence times has been investigated. The system exhibits periodic thermokinetic oscillations and overshoots which are either hot ignitions or cool flames.

ISSN:0010-2202    

DOI:10.1080/00102208508960289

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

In this paper we describe and test the use of a thermogravimetric technique for measuring the ignition temperatures of thin layers and beds of coal particles, and we report the results of such measurements on a South African coal, a Polish coal and two chars. The technique is to compare weight-temperature curves in air and inert (N2) atmospheres in order to evaluate the ignition temperature; the results are used to test the existing theory and to obtain kinetic constants for the reactions.

ISSN:0010-2202    

DOI:10.1080/00102208508960290

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The analogy between a sooting hydrocarbon flame and a stoichiometric flame front seeded with alkaline metals is studied. It is found that under certain conditions they are very similar as far as their electrical behaviour is concerned. Theoretical and experimental demonstration is made that the presence of a thermal ionization zone in the post-flame region is the cause of a large decrease of the potential necessary to extract a given current from the flame front. However, the saturation current extracted from the flame is very close to the saturation current measured in the absence of any thermal ionization. The consequence of the similarity of behaviour is that an ionic mechanism of nucleation of soot initiated by the flame chemi-ions appears to be insignificant compared to a pure radical mechanism of nucleation. The presence of positively charged soot particles in the post flame region of sooting hydrocarbon flames must be explained by the thermal ionization of large hydrocarbon molecules with low ionization potentials (around 5 eV)

ISSN:0010-2202    

DOI:10.1080/00102208508960291

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper investigates the utility and accuracy of the use of fine-wire thermocouples for time resolved thermometry in turbulent flames. The problem, if course, is that there is no unique time constant in a turbulent flame with widely fluctuating temperature. An analytical formulation is presented which shows that while little error may be expected in determination of r.m.s. values of temperature, there may be a substantial error made in deduction of the mean temperature, under certain circumstances. Experimentally, in a premixed methane-air flame, a comparison is made of a time resolved compensated thermocouple measurement with a simultaneous measurement by molecular Rayleigh scattering, and the results compared with the theoretical predictions. The thermocouple, compensated through a single time constant, behaved admirably, under these conditions.

ISSN:0010-2202    

DOI:10.1080/00102208508960292

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The effect of distributed obstacles on flame propagation in gaseous media is studied numerically using a two-dimensional combustion hydrodynamic model. The method is applied to the problem of deflagration underneath a column-supported storage tank, idealized by a horizontal slice across the column array. Dimensions of the model problem are scaled down to expedite the computation. Numerical simulations confirms that distributed obstacles can accelerate a flame to many times its nominal speed. The results show that obstacles' cross-sectional area and separation distance are important factors in determining flame acceleration. The specific distribution of obstacles can also affect the speed of the flame, though not as much as the obstacles' size. The primary mechanism of flame acceleration in this study appears to be the aerodynamic effect due to obstruction of the flow. Also, the fastest moving flame branches are those propagating along line of-sight paths between the obstacles. The rate of flame propagation along each flame branch is controlled predominantly by the local flame and flow characteristics. The implication of these findings on the design of liquefied gaseous fuel (LGF) storage facilities are discussed.

ISSN:0010-2202    

DOI:10.1080/00102208508960293

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A new simple formula for calculating the adiabatic flame temperature of fuel/air mixtures has been developed. The formula is usable in a wide range of both fuel and reaction variables. Among the fuels considered for the formula are members of the paraffin, aromatic, olefin and alcohol families, and hydrogen and acetylene. The formula is functionally expressed in terms of the fuel/air ratio, the reaction pressure, the initial mixture temperature and the number of carbon atoms in the individual fuel. By using the formula, the adiabatic flame temperature for a designated fuel and reaction condition can be found within an accuracy of one percent.

ISSN:0010-2202    

DOI:10.1080/00102208508960294

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This short paper describes the application of the flamelet modelling approach to the prediction of the species concentration field in a turbulent propane-air flame. The structure of the laminar flamelet, the microscopic element in the model, is computed using a semi-global expression for fuel disappearance in conjunction with an established reaction scheme for the oxidation of CO and H2.

ISSN:0010-2202    

DOI:10.1080/00102208508960295

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The effect of prior gamma irradiation on the thermal decomposition, ignition and combustion of coal has been studied using thermogravimetry, differential thermal analysis and isothermal techniques. Data indicate that for high ash containing coals the thermal decomposition is drastically catalysed, the ignition temperature is lowered very significantly and the flame duration is increased by gamma irradiation.

ISSN:0010-2202    

DOI:10.1080/00102208508960296

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper describes the structure of a turbulent boundary layer with premixed combustion and massive blowing of the reactant mixture, i.e. when the inverse of the injection rate can be considered as a small parameter. Comparison with experimental data is presented for the mean and intensity of the streamwise velocity.

ISSN:0010-2202    

DOI:10.1080/00102208508960297

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor