Things will get a little technical now…The best way to solve the problem of high-speed flight is to use variable cycle engines like turbo-ramjets. As the name indicates, it is a cross between a turbojet and a ramjet. What it does, is that it operates as a turbojet at low speeds and as a ramjet at high Mach numbers. The best of both worlds. The engine philosophy is that no single engine can satisfy flight requirements of a vehicle with an operational speed range of 0 to Mach 5.
My project deals with the computational performance analysis and mixer analysis of turbo-ramjet engines. I finished the on design and off design analysis of both separate exhaust configuration and mixed flow configuration. The mixer analysis was performed computationally by using CFX-Tascflow. Results
The main problem with the mixed flow configuration is that during the transition between the turbojet phase and the mixed flow phase, due to the large mismatch in total pressures, flow may reverse into the ramjet duct making the transition a failure. Now by exerting a control on the Turbine Inlet Temperature (T.I.T) and with the use of variable geometry at the mixer entrance, the transition may be made possible. With this method the transition point may be brought down to Mach 1.5.