Method for Calculating Effects of Dissociation on Flow Variables in the Relaxation Zone Behind Normal Shock Waves
Method for Calculating Effects of Dissociation on Flow Variables in the Relaxation Zone Behind Normal Shock Waves

Author: John S. Evans

Publisher:

Published: 1956

Total Pages: 668

ISBN-13:

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Because the chemical reaction rates needed to predict the dependence of degree of dissociation on distance behind the shock are not known, order-of-magnitude estimates of their values have been used in a numerical example, the purpose of which is to illustrate the use of reaction-rate equations to predict relaxation time and distance behind the shock front.

A Technique for Determining Relaxation Times by Free-Flight Tests of Low-Fineness-Ratio Cones; With Experimental Results for Air at Equilibrium Temperatures Up to 3440 K
A Technique for Determining Relaxation Times by Free-Flight Tests of Low-Fineness-Ratio Cones; With Experimental Results for Air at Equilibrium Temperatures Up to 3440 K

Author: Jack D. Stephenson

Publisher:

Published: 1960

Total Pages: 64

ISBN-13:

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This report describes a technique which combines theory and experiments for determining relaxation times in gases. The technique is based on the measurement of shapes of the bow shock waves of low-fineness-ratio cones fired from high-velocity guns. The theory presented in the report provides a means by which shadowgraph data showing the bow waves can be analyzed so as to furnish effective relaxation times. Relaxation times in air were obtained by this technique and the results have been compared with values estimated from shock tube measurements in pure oxygen and nitrogen. The tests were made at velocities ranging from 4600 to 12,000 feet per second corresponding to equilibrium temperatures from 35900 R (19900 K) to 6200 R (34400 K), under which conditions, at all but the highest temperatures, the effective relaxation times were determined primarily by the relaxation time for oxygen and nitrogen vibrations.

Measurements of the Dissociation Rate of Molecular Oxygen
Measurements of the Dissociation Rate of Molecular Oxygen

Author: Charles J. Schexnayder

Publisher:

Published: 1961

Total Pages: 28

ISBN-13:

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The ability of molecular oxygen to absorb light in the Schumann-Runge ultraviolet region of the spectrum has been used to follow the change in concentration of molecular oxygen as a function of time behind shock waves in oxygen and in a mixture of 10-percent oxygen in argon. Analysis of the records obtained yielded values for the dissociation rate of oxygen as a function of temperature over the range 4,000° to 10,000°K. The highest previously reported experimental results in the literature were at 7,500°K.