A systematic literature review based on different fuel injection strategies used in scramjet combustors

A supersonic combustion ramjet engine is an air-breathing propulsive system aimed at futuristic hypersonic vehicles. The profound advantages observed in the area of defence applications has attracted researchers' attention towards improving the fluid flow dynamics of scramjet engines. The present effort summarizes the fundamental problems and latest advances in fuel injection techniques. Improvements and application of modern fuel injection technologies have a profound impact on the scramjet engine, increasing capacity in terms of flight speed, efficiency in fuel mixing, and combustion. The fuel injection system has a direct impact on the engine's combustion processes, determining the scramjet engine's thrust power and its flight speed. A systematic database including brief descriptions of mixing enhancement mechanisms was analyzed numerically and experimentally, identifying the needed and existing fuel injection strategies. The numerical and computational analysis directly related to the experimental investigations is also included.