Performance Evaluation of Ramjet Engines: Supersonic Combustion vs. Shock Induced Combustion

Abstract

The Supersonic Combustion Ramjet (scramjet) engine is currently the only air-breathing engine that can achieve hypersonic speed. It has the potential to replace traditional propulsion systems for air and space transportation systems with a faster and more efficient way. However, the engine's efficiency decreases beyond a Mach number of 10 due to low residence time. To address this issue, a specific type of oblique detonation wave engine, known as shock induced combustion ramjet (shcramjet), has been developed. A code has been developed to analyse and compare the performance of Scramjet and shcramjet engines. The code uses oblique shock relations to analyse the performance of Scramjet engines, while for shcramjet engines uses Chapman-Jouguet detonations. The results are then compared with performance parameters like specific thrust, specific impulse, specific fuel consumption, propulsive power, thermal and overall efficiencies by varying Mach numbers. A particular case study involving the combustion of H2 with air under stoichiometric conditions is showcased and examined in detail using CFD at Mach 9 and 10. The results reveal that the shcramjet engine exhibits superior performance compared to the scramjet engine. Shcramjet produced nearly 8% greater combustion than generated in scramjet engine.