ISSN:0010-2202    

DOI:10.1080/00102206908952192

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The ignition of a cold combustible mixture has been investigated at the forward stagnation region of a hot projectile. The occurrence of temperature maxima at the surface of the projectile acts as the ignition criterion. For quasi-stationary analysis, the characteristic (unknown) parameter of the problem is the surface (or ignition) temperature. The steady boundary layer equations describing the reacting flow have been solved numerically and the ignition temperatures for propane-air mixture are calculated for different values of the various non-dimensional physical parameters.

ISSN:0010-2202    

DOI:10.1080/00102206908952193

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The problem of ignition and extinction for the flow of a compressible fluid with competitive/chain reactions has been considered in the present paper, A typical system of hydrogen-carbon monoxide fuel mixture forming one end of the opposed jet and air the other end has been considered for the numerical study. An efficient numerical procedure has been developed for the solution of two coupled and non-linear second order differential equations describing the chemical kinetics. The present study reveals that the mass flow rates at extinction (Apparent Flame Strength) for the mixture can be obtained by using a simple mixing rule similar to those used in theories of flame propagation. The results of maximum volumetric heal release rates have been obtained and compared with the experimental results of Bittker and Brokaw.

ISSN:0010-2202    

DOI:10.1080/00102206908952194

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

In view of the destructive ignitions that occur in hypergolic test firings of attitude-control motors under simulated high-altitude conditions, the preignition behavior of MMH, UDMH, A-50 and N2H4with N2O4was examined at low pressures and temperatures in the laboratory. At low NO2pressures and temperatures, such as those that would be encountered in combustion chambers during starts in space, the ignition of these fuels was significantly delayed. During the preignition period, relatively involatile reaction products were formed between NO2. and the fuels. Infrared spectrophotometry, mass spectrometry, differential thermal analysis, and other techniques were used to examine these preignition residues. The IR absorption curves were consistent with the view that the major component in the MMH residue that could behave as an explosive monopropellant was MMH.nitrate, IR spectra of the preignition residues formed with N2H4or A-50 suggest that hydrazine nitrate was the major constitutent of these residues. The preignition residues probably are a corrosion and a contamination threat to equipment on the exterior of flight vehicles.

ISSN:0010-2202    

DOI:10.1080/00102206908952195

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The quasi-steady adiabatic vaporization and subsequent exothermic decomposition of a pure monopropellant spherical droplet is examined in the absence of free and forced convection. The Lewis number is fixed at unity and linear variation of the universal diffusion coefficient with temperature is adopted. A direct one-step first-order decompositional burning is postulated. By means of inner-and-outer (matched asymptotic) expansions the vaporization rate is analytically determined for cases in which the ambient atmosphere is inert with respect to the product of decomposition. Both the case of very large and very small first Damkohler number is considered (where the first Damkohler number is the ratio of the rate of reaction to the rate of mass diffusion). Then a two-step irreversible reaction model is examined for the case in which the ambient atmosphere is reactive, in bipropellant fashion, with the product of decomposition. Conditions for sequential concentric flames are described.

ISSN:0010-2202    

DOI:10.1080/00102206908952196

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

In this paper high frequency combustion chamber oscillations of two different types are studied analytically. The first kind of oscillation treated is the purely transverse mode found in an annular motor. The second type of oscillation studied is the longitudinal mode in a cylindrical chamber. For both types of oscillation the combustion processes are represented using the sensitive time lag model. The sources of mass and energy due to combustion are taken to be distributed in a more or less arbitrary way in the axial direction. A nonlinear perturbation analysis, employing the technique of coordinate stretching is carried out and results, for both types of oscillation, in a nonlinear ordinary differential equation governing the shape of the nonlinear periodic waves. In both cases the governing equation can be transformed into an equation that has been previously solved in studies of concentrated combustion. In the case of the transverse oscillations both standing and travelling waves are considered and the configuration of the shock in the case of discontinuous oscillations is determined.

ISSN:0010-2202    

DOI:10.1080/00102206908952197

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor