Design and Performance of Hypersonic Intake for Scramjet Engine

Rockets are the only vehicles to reach hypersonic speeds with non-airbreathing engines carrying both fuel and oxidizer increasing budget of space exploration. So, the desire to achieve hypersonic speeds at low cost has led to the development of air-breathing engines known as supersonic combustion ramjet engines or scramjet engines. The most complex part in the development of the scramjet engine is the intake. Free-stream hypersonic speed flow will be compressed in intake and processed into the combustor as per the required pressure and temperature. The high-pressurized flow can be provided to the combustor based on the strength of shocks attained in the intake due to ramps. So, the design of intake depends on the number of ramps and the angle of ramp, which decides the strength of shock for compression. All the scramjet intakes designed based on oblique shock theory will start efficiently in the designed conditions, but the main problem is unstarting the performance of intake at off-design conditions. It is very important to know the flow behavior at off-design conditions to enhance the operating range of the engine. So, in this chapter, a detailed procedure for the design of hypersonic intake and techniques to mitigate the unstarting conditions of scramjet engines is discussed.