Investigation of Superdetonative Ram Accelerator Drive Modes
Final technical rept. 1 Jul 1988-30 Jun 1989
WASHINGTON UNIV SEATTLE AEROSPACE AND ENERGETICS RESEARCH PROGRAM
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This report presents the results of experimental and theoretical investigations of high velocity modes of the ram accelerator, a ramjet-in-tube projectile accelerator whose principle of operation is similar to that of a supersonic airbreathing ramjet. The projectile resembles the centerbody of a ramjet and travels through a stationary tube filled with a premixed gaseous fuel and oxidizer mixture. The tube acts as the outer cowling of the ramjet, and the combustion process travels with the projectile, generating a pressure field which produces forward thrust on the projectile. Different modes of combustion have been explored for accelerating projectiles of nearly identical geometry. Subsonic, thermally choked combustion theoretically allows a projectile to be accelerated to the Chapman-Jouguet C-J detonation speed of a particular gas mixture. In the superdetonative regime the same projectile is accelerated while always traveling faster than the detonation speed, and in the transdetonative regime 85-115 of detonation speed the same projectile may transmit smoothly from a subsonic to a supersonic to a superdetonative combustion model. This report examines operation in these three regimes of flow up to velocities approaching 2500 ms in a 12.2 m long, 38 mm bore ram accelerator, using projectiles of 45-75 gm mass.
- Air Breathing Engines (Unconventional)