Accession Number : AD0693341

Title :   DIFFUSION FLAMES AND SUPERSONIC COMBUSTION.

Descriptive Note : Final scientific rept. Apr 67-Apr 68,

Corporate Author : INSTITUTO NACIONAL DE TECNICA AEROESPACIAL MADRID (SPAIN)

Personal Author(s) : Da-Riva,I. ; Linan,A. ; Fraga,E. ; Urrutia,J.

Report Date : JUN 1969

Pagination or Media Count : 33

Abstract : The method of matched asymptotic expansions has been used for the analysis of the H2-Air reaction in the temperature and pressure range of interest to Supersonic Combustion. The use of the method is advantageous because of the large differences in the rate constants of the elementary reactions appearing in the reaction mechanism. The ratios between the rate constants are used as the small or large parameter in the perturbation method. Several stages are found in the course of the reaction and at each stage only a small number of the elementary reactions play an important role. Different expansions are used for each stage, and they are matched according to the rules of the method of matched asymptotic expansion of Kaplun, Lagerstron, etc. For the zeroth order approximation, at each stage, the reaction mechanism is very often drastically simplified. This occurs because some of the elementary reactions are 'frozen' while others are at equilibrium; some species are not changing at a given stage, while others take a quasi-steady state value. Very often an overall reaction rate may be used for the zeroth order approximation at each stage. The method of matched asymptotic expansions allows to determine how the appropriate overall reaction rate changes with the succesive stages of the reaction and with the initial stoichiometry of the mixture. (Author)

Descriptors :   (*SUPERSONIC COMBUSTION RAMJET ENGINES, SUPERSONIC COMBUSTION), (*SUPERSONIC COMBUSTION, REACTION KINETICS), ASYMPTOTIC SERIES, PERTURBATION THEORY, APPROXIMATION(MATHEMATICS), CHEMICAL REACTIONS, THREE PHASE FLOW, IGNITION LAG, SPAIN

Subject Categories : Combustion and Ignition

Distribution Statement : APPROVED FOR PUBLIC RELEASE