ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
A method of studying solid propellant ignition is described which utilizes detonating gas igniters. This article describes (1) conditions required for obtaining reproducible igniter systems and (2) results of application of the method to four well-known rocket propellants in which various “chemical” and “thermal” effects were brought out by suitable variations in the initial pressure and composition of the detonating gas igniter. Successful application of the detonating-gas-igniter method requires the use of steady state detonation waves, i.e., waves in which the detonation head has attained a steady “size” and momentum. Experimental data are presented which show that detonation (following the initial predetonation buildup) must travel 40 to 50 cm. in a 1-in. diam. steel tube before these steady state conditions are established in the systems studied.Results of studies by the detonating gas ignition method show that, besides the important purely physical effects of temperature and pressure, free oxygen and solid carbon in the igniter system are very effective in lowering the threshold ignition pressure. Moreover, increasing oxygen in the igniter markedly lowers the ignition time lag (τp) for appearance of an observable flame although it increases the time lag (τi) for appearance of reaction sufficient to cause the first measurable ionization in the reaction zone (τp ≫ τi). Although true flame-ignition time lags were observed to be of the order of several milliseconds, reaction of the propellant was observed to start within 1 msec. (possibly immediately) after collision of the detonation wave with the propellant.The detonating gas method is shown to provide a reliable measure of the relative ignition sensitivities of various rocket propellants.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690010319
