Shcramjet

A shock-induced combustion ramjet engine (abbreviated as shcramjet; also called oblique detonation wave engine; also called standing oblique detonation ramjet (sodramjet); or simply referred to as shock-ramjet engine) is a concept of air-breathing ramjet engine, proposed to be used for hypersonic and/or single-stage-to-orbit propulsion applications.

Design

The shcramjet engine geometry is simple and similar to scramjet, varying only in the combustor design. The engine includes a supersonic inlet followed by a combustion chamber and a nozzle, respectively. The inlet design is similar to a scramjet, in which the whole nose structure is used as inlet. Combustion in a shcramjet can occur in shock-induced combustion or detonation combustion, depending on the strength of the inducing shock. If ignition occurs far enough downstream that the ensuing combustion process does not influence the preceding shock, the combustion is said to be shock-induced. However, for extremely fast reactions, ignition occurs close to the preceding shock wave and the combustion couples with the shock wave and forms a detonation wave. Therefore, detonation wave ramjet, or oblique detonation wave engine, is a particular case of shcramjet.

Though shock and detonation waves are related to high pressure loss during combustion, the theoretical total pressure loss associated with shcramjet combustor approaches that of the scramjet engine at increasing mach numbers. This fact, together with the simpler engine geometry with concomitant increase in component efficiencies, results in superior predicted performance at flight Mach numbers beyond 12.