The effects of heat release were studied in a planar, gaseous reacting
mixing layer formed between two sub-sonic freestreams; one containing hydrogen
in an inert diluent, the other containing fluorine in an inert diluent.
Sufficiently high concentrations of hydrogen and fluorine reactants were
employed to produce adiabatic flame temperature rises of up to 940 K (adiabatic
flame temperature of 1240 K absolute). Although (he displacement thickness
of the layer for a zero streamwise pressure gradient showed an increase
with increasing heat release, the actual thickness of the mixing layer
at a given downstream location was not observed to increase and, in fact,
was characterized by a slight thinning. The overall entrainment into the
layer was seen to be substantially reduced by heat release. The large-scale
vortical nature of (he flow appeared to persist over all levels of heal
release in this investigation. Imposition of a favorable pressure gradient,
though resulting in additional thinning of the layer, was observed to have
no resolvable effect on the amount of chemical product formation and hence
on the mixing.