摘要:

Continuum theory is used to describe the steady spherically symmetric state of an unbounded expanse of slightly ionized gas about a perfectly catalytic conductor. Far from the sphere the gas is in chemical equilibrium, but at finite distances finite-rate ionization and recombination may occur according to a direct one-step reversible reaction in which either a neutral or an electron (the negative-charge carrier) participates as the third body in the recombination process. The limit of large Debye number appropriate to the use of small electrostatic probes in slightly ionized gases (where the Debye number is the ratio of the Debye length to the probe radius) is examined. In this limit the case of nearly frozen chemistry near the sphere is of greatest practical interest; modification of current collected from the value given by Su and Lam, owing to incipient reaction effects, is determined for negative potential bias applied at the probe.

ISSN:0010-2202    

DOI:10.1080/00102206908952213

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Analyses appearing in the literature on combustion of cellulosic fuels assume that the energy transfer in the fuel interior is adequately described by an unsteady state conduction equation provided with an Arrhenius source. It has been discovered experimentally by x-ray photography that even though in certain zones of space and time the above assumption is valid, there exist other zones in which several ‘secondary’ physico-chemical effects of energy evolution and transfer become non-negligible and take a dominating role in the control of the burning rate. The present paper gives a critical summary of the ‘secondary’ processes of energy and mass evolution and transport in wood-burning, in an attempt to formulate them in such a way that a meaningful quantitative handle is possible.

ISSN:0010-2202    

DOI:10.1080/00102206908952214

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Two-dimensional transonic flows which are bounded by a free surface and a wall and which have interior heat release are investigated theoretically. It is shown that under certain conditions a supersonic-subsonic transition is possible, in contrast to flows bounded by two walls, while maintaining a positive pressure coefficient on the free surface when the free surface is formed by an adjacent supersonic or transonic flow. The problems investigated correspond to outer limits in the sense of matched asymptotic expansions and arbitrary initial conditions cannot be satisfied; however, several practical problems yield initial conditions which fortuitously match the outer limit conditions. Application to problems of external burning for control or propulsion is indicated.

ISSN:0010-2202    

DOI:10.1080/00102206908952215

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

ISSN:0010-2202    

DOI:10.1080/00102206908952216

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The surface structure of propellants containing various oxidizers and polyurethane binder burning at pressures between one atmosphere and 800 psia is presented. These propellants, which contained ammonium perchlorate, potassium perchlorate or cyclotetramethylenetetranitramine as the oxidizer, were viewed while burning using cinephotomicrography, and as quenched samples using a scanning electron microscope (SEM). From these data the microstructure of the burning propellants was inferred. Results not only show why certain phenomena, such as the self-quenching of ammonium perchlorate-polyurethane propellants, occur, but also serve as a basis for checking existing analytical models and developing more accurate models for solid propellant combustion.

ISSN:0010-2202    

DOI:10.1080/00102206908952217

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

This paper describes experimental studies of the combustion of single particles of aluminum and beryllium in a variety of oxidizers. Experiments were performed using both a pulsed Nd-glass laser and a xenon flash heating device as ignition sources. A scanning electron microscope (SEM) served as the major diagnostic tool in particle quenching studies. Major differences in the combustion of aluminum and beryllium have been found and have been related to the thermophysical properties of the metals and their respective oxides. New data on the burning rate of laser-ignited aluminum particles are presented. Scanning electron microscope pictures of the evolution of geometry of burning beryllium particles are presented. The effect of water vapor on the combustion of beryllium particles is documented. A discussion of the mechanism of metal particle fragmentation is included.

ISSN:0010-2202    

DOI:10.1080/00102206908952218

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

An experimental investigation was conducted for determining the combustion characteristics of bi-phase rockets. The experimental results were compared with the Priem-Heidmann propellant vaporization model and the Priem-Guentert non-linear instability model.

ISSN:0010-2202    

DOI:10.1080/00102206908952219

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor