| || Detonation Type Ram Accelerator: A Computational Investigation
Author : Sunil, Bhat
Source : Defence Science Journal ; Vol:50(1) ; 2000 ; pp 3-11
Subject : 629.7 Aeronautics;531.55 Projectiles;623.4 Armaments and Ballistics
Keywords : RAM accelerators;Flow processes;Supersonic flow;Conical shock waves;Supersonic combustion;Wave angle theory;Waves
Abstract : An analytical model explaining the functional characteristics of detonation type ram accelerator is presented. Major flow processes, namely, (i) supersonic flow over the cone of the projectile,(ii) initiation of conical shock wave and its reflection from the tube wall, (iii) supersonic combustion, and (iv) expansion wave and its reflection are modelled. Taylor-Maccoll approach is adopted for modelling the flow over the cone of the projectile. Shock reflection is treated in accordance with wave angle theory for flows over the wedge. Prandtl-Mayer analysis is used to model the expansion wave and its reflection. Steady one-dimensional flow with heat transfer along with Rayleigh line equation for perfect gases is used to model supersonic combustion. A computer code is developed to compute the thrust produced by combustion of gases. Ballistic parameters like thrust-pressure ratio and ballistic efficiency of the accelerator are evaluated and their maximum values are 0.032 and 0.068, respectively. The code indicates possibility of achieving high velocity of 7 km/s on utilising gaseous mixture of2H2 + O 2 in the operation. Velocity range suitable for operation of accelerator lies between 3.8 -7.0 km/s. Maximum thrust value is 33721 N which corresponds to the projectile velocity of 5 km/s.