Computational studies of a superdetonative ram accelerator mode

A computational study of a ramjet-in-tube concept known as the accelerator'9 is presented. The analysis assumes inviscid flow, and employs a total variation diminishing (TVD) numerical scheme that includes nonequilibrium chemistry, real gas effects, and a 7-species, 8-reaction combustion model for hydrogen/oxygen mixtures. This numerical formulation gives a more accurate model for the combustion process and is computationally more efficient than previous numerical studies conducted on the ram accelerator. The flow, combustion, and performance characteristics of the ram accelerator are investigated for several projectile configurations in the superdetonative velocity range of 5.0-10.0 km/s. The distribution of various physical quantities along the ram accelerator, as well as temperature contours, are presented. Plots of ballistic efficiency and thrust pressure ratio are also included. Ballistic efficiencies of up to 28% and thrust pressure ratios as high as 17% are obtained. The results also show that efficient acceleration of projectiles is possible through velocities as high as 9 km/s.