EXPERIMENTS ON BLUNT BODY FLOWS WITH CENTRAL INJECTION.
MASSACHUSETTS INST OF TECH CAMBRIDGE AEROPHYSICS LAB
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Blunt nosed models incorporating axisymmetric contoured injection nozzles were tested at Mach numbers of 7.46 and 4.80. Nozzle contours were computed by means of an inviscid, incompressible analysis and designed to generate hemispherical and ellipsoidal interfaces between the injectant and external flow fields. Shock and interface displacement measurements were in substantial agreement with earlier data, provided a consistent definition of injection mass flow rate was used. Injection produced substantial reductions in equilibrium surface temperatures. Helium proved to be a more effective injectant in this respect than air. In the hypersonic range, Mach number appeared to have no effect on the results. It appeared that in most cases the injectant separated from the nozzle near the throat, producing considerable mixing within the injection cap, accompanied by unsteadiness and asymmetry of the bow shock and interface. It was found that separation data could be correlated on the basis of a previously developed throat flow rate parameter and that separation could be successfully postponed by increasing the throat area. Author