Optimization of Ram Accelerator Systems Design

Abstract

Anumerical procedure for optimizing the performance of ram accelerator hypersonic launchers, by variationof the reactingmixturechemistry, is presented. The calculationsare performed by a specially developedprogram that includes a computational  uid dynamics solver for the reacting  owŽ eld solution and an optimization algorithm. The thrust coefŽ cient is taken as the objective function and existing constraints are treated by the exterior penalty method. To illustrate the procedure, optimized solutions are found for a multistage launcher, whose mission is to accelerate projectiles, weighing 0.1 and 100 kg, from 2500 to 9700 m/s. Preliminary investigation of projectile geometric parameters is conducted and shows that they have remarkable effects on the performance of a superdetonative ram accelerator system. Inviscid  ow is assumed.The procedure is general and can be used to optimize ram accelerators operating in any of the three establishedmodes: thermally choked, transdetonative, and superdetonative. It also makes possible the estimation of the performance limits for such systems. It is concluded that to obtain realistic solutions, existing limitations and the effect of viscosity should be included in the optimization model. Directions for future research are suggested.