Accession Number : AD0663741

Title :   DIFFUSION FLAMES AND SUPERSONIC COMBUSTION.

Descriptive Note : Final rept.,

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

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

Report Date : 01 OCT 1967

Pagination or Media Count : 53

Abstract : Some problems related to the fluid dynamical and chemical phenomena appearing near the injector exit of an idealized supersonic combustion burner, are theoretically investigated. The ignition delay length is calculated under the assumption that fuel(hydrogen) and oxidizer (air) mix without appreciable concentration change and heat release resulting from chemical reactions, although radicals, mainly atomic hydrogen, are produced. The chemical kinetics scheme is reduced to one overall chemical reaction. The presence of radicals introduced in the mixing zone from outside is taken into account. The fluid dynamic pattern corresponds to a two-dimensional constant pressure shear layer. It is shown that dissociation at the injector outer boundary layer controls in many cases the ignition delay length. Since when hydrogen is injected into a coflowing supersonic stream of air, a wake-like recirculating configuration appears, the ignition delay lengths were compared with some experimental data on near wake lengths, to show that, in most cases of interest, recirculation would enhance the ignition mechanism. (Author)

Descriptors :   (*SUPERSONIC COMBUSTION, REACTION KINETICS), (*FLAMES, SUPERSONIC COMBUSTION), HYDROGEN, AIR, IGNITION LAG, INJECTORS, FLUID DYNAMICS, FREE RADICALS, TWO DIMENSIONAL FLOW, DISSOCIATION, WAKE, THEORY, SPAIN

Subject Categories : Combustion and Ignition

Distribution Statement : APPROVED FOR PUBLIC RELEASE