Numerical Investigation of the External Propulsion Ram Accelerator.
Final rept. Apr-Dec 94,
ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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Computations of the hypersonic flow of a combustible mixture over a projectile are presented. A projectile of maximum diameter is launched into a 120-mm diameter gun tube at Mach numbers of 6-1O. The gun tube is sealed at both ends with diaphragms and filled with a fuel rich methane oxygen nitrogen mixture at an initial pressure of 50 atm and temperature of 300 K. Combustion is established on the projectile by a small forward facing step positioned on the projectile. Results demonstrate that step heights of 0.5, 1, and 1.5 mm cause detonation of the mixture at the step with sustained combustion over the afterbody and base of the projectile. The interaction between the bow and shock from the conical forebody and the detached shock detonation on the forward facing step, positioned at the forebody afterbody juntion, results in confinement of a combustion layer around the projectile afterbody. The resulting high pressure and temperature combustion products, which are confined to this layer, are expanded into the projectile wake, generating thrust. Navier Stokes, computational fluid dynamics, reacting flow, detonation, kinetics, ram accelerator, external propulsion.
- Combustion and Ignition