Experimental and numerical investigation of smooth turbine-based combined-cycle inlet mode transition

Smooth transition from turbojet to ramjet mode is critical to turbine-based combined-cycle (TBCC) propulsion system. Wind tunnel tests and numerical simulation were conducted to investigate the method of smooth inlet mode transition, and acquire corresponding inlet flow details. Steady-state pressure distribution was recorded in the experiment to evaluate inlet performance. Combined experimental and numerical investigation results indicate that smooth inlet mode transition can be achieved by keeping the total throttle ratio of the TBCC inlet constant. When the total throttle ratio is equal to 56%, the Mach number and the flow ratio of aerodynamic interface plane (AIP) would be basically equal to 0.22 and 0.50, respectively. Meanwhile, the terminal shock wave is located near the throat of the inlet during the mode transition. This paper puts forward the method of smooth mode transition of tandem-type turbine-based combined-cycle inlet and provides the flow details during this process.