| Summary: | A combustion driven hypersonic shock tunnel has been designed and constructed primarily for the simulation of flows around hypersonic ramjets. This report describes the design and construction of the shock tunnel and discusses its hypersonic simulation capabilities. The construction of the shock tunnel has now been completed and it is ready for instrumentation and calibration. The driving gas is a combustible mixture of stoichiometric hydrogen and oxygen diluted with 60 to 75% helium to avoid detonation. The maximum mixture loading pressure is 2000 psi. The driven gas is air, usually at room temperature and pressure. Successful evacuation of the test section to 5 microns of mercury has been achieved. The shock tunnel has been designed to produce air at minimum stagnation temperature and pressure of 4200°R and 2300 psi respectively and 0 maximum stagnation temperature and pressure of 14300°R and 20,000 psi respectively1 at the nozzle entrance. Air at these stagnation conditions, when expanded in the test section, will completely simulate free flight conditions (i.e., pressure, temperature, unit Reynold's number, Mach number, etc.) in and around a hypersonic ramjet flying over an altitude range of 90,000 ft to 250,000 ft and a corresponding Mach number range of 7.5 to 18.5. Preliminary tests have been successful and have indicated that (a) the recoil mechanism is capable of absorbing the shock forces, (b) the gun barrels, joined end to end, produce a well aligned, rigid and strong driven section and (c) the actual recoil stroke will probably be considerably less than the initially assumed value of 4".
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