摘要:

The burning rate behaviour of a series of bimodal PETN/Polyurethane (PU) and RDX/PU propellants have been examined to determine the effect of binder and oxidizer concentration, and coarse to fine ratio of oxidizer particles on burn rate. Evidence for an oxidizer interaction has been found in mixed PETN/RDX/PU propellants. Catalysis of the PETN/PU, RDX/PU and PETN/RDX/ PU propellants by a metal oxide has been investigated. Catalytic enhancement in both the condensed phase and gas phase has been observed. Oxidizer interaction between PETN and RDX can lead to substantial increases in burning rate in the presence of catalyst.

ISSN:0010-2202    

DOI:10.1080/00102208808923940

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

For the basic investigation of a premixed flame subjected to the effects of both flame stretch and flame curvature, the characteristics of the outward propagating cylindrical flame formed in an axially stretching flow were theoretically analyzed and compared with those of counter-flow twin flames, which have no curvature, and other types of non-stretched flames. The flame sheet model was first adopted for the parametrical investigation of the effects of Lewis number and preferential diffusion. Then, the finite reaction rate model was used and the extinction characteristics were analyzed over a wide range of equivalence ratios, resulting in the agreement of the extinction limit curves with the experimental data reported before.

ISSN:0010-2202    

DOI:10.1080/00102208808923941

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

In this paper we consider the influence of centrifugal arid Coriolis accelerations on the form and stability of a flame propagating in a rotating tube. We detect a discrete sequence of angular velocities, near which the flame propagation velocity undergoes an unlimited amplification. We show that sufficiently rapid rotation may suppress cellular instability of the flame front. We construct a self-similar solution that describes a flame propagating in a rotating gas in free space. Our predictions of the flame shape and of the suppression of cellular instability in the presence of rotation have been verified in a simple experiment we have performed.

ISSN:0010-2202    

DOI:10.1080/00102208808923942

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A char combustion model based on percolation theory is developed. The concept of percolation is used to derive the time and position dependent transport and structural properties of the char particle during combustion. By adopting existing kinetic parameters for the surface reaction of the char particle, porosity and oxygen concentration profiles within the particle are calculated for progressive carbon conversion values. Assuming an initially uniform porosity of the char particle, and a Bethe lattice to describe the pore structure, a critical porosity is calculated at which the particle surface layer breaks into fragments. The effects of particle diameter, combustion temperature, pore structure, and fragmentation porosity upon particle reactivity and burnout times are evaluated to determine the sensitivities of the results to the assumption of initial and operating conditions. The impact of fragmentation on the fly ash particle size distribution during pulverized coal combustion is discussed.

ISSN:0010-2202    

DOI:10.1080/00102208808923943

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Measurements of the velocity and concentration distributions for an air jet containing fine particles of coal of mean diameter 30 mm were made in the fully developed region between 20 and 60 nozzle radii. An analytical model is developed using Field's two phase entrapment equation and the predictions for the structure of the jet tally with the experiments.

ISSN:0010-2202    

DOI:10.1080/00102208808923944

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Simplification of a detailed reaction mechanism is possible if there exist independent, approximate relations which permit calculation of concentrations of some species in terms of other known concentrations. Given these independent relations, a general procedure has been developed for combining a set of elementary chemical reactions into a reduced mechanism.

ISSN:0010-2202    

DOI:10.1080/00102208808923945

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor