Thermodynamic Process and Performance Analysis of Inter-Stage Turbine Rotating Detonation Turboshaft Engine

A lumped parameter model was established for the turboshaft engine based on the concept of inter-stage turbine rotating detonation. With different detonation combustion characteristics, change rules of engine parameters are investigated such as the internal temperature, pressure, the mass flow allocation and the turbine efficiency. The results indicate that introducing a rotating detonation combustor between turbine stages could reheat and recompress the gas, and then increase the specific power of the turboshaft engine significantly. Simultaneously, it will also change the distribution ratio between the engine mainstream flow and cooling flow, which influences the flow coefficient and the stage loading factor of turbine and decreases the turbine efficiency. For the T700 turboshaft engine assisted by the inter-stage turbine rotating detonation combustor, the optimal detonation temperature rise is 560K, the specific power of the engine increases by 36.9%, and the specific fuel consumption increases by 14.6%. Compared with the engine with high thermal-cycle parameters (compressor pressure ratio πC=21, outlet total temperature of main combustion T4*=1900K), the performance improvement of the engine with medium/low thermal-cycle parameters(πC=13~17, T4*=1500~1700K)is more obvious after introducing the inter-stage turbine rotating detonation combustor. Different from the development route of high thermal-cycle parameters, the research of variable-cycle turboshaft engine that operates in the high-power detonation mode during the take-off phase and in the conventional engine mode during cruise will provide a useful technical support for the turboshaft engines development in the future. © 2022, Editorial Department of Journal of Propulsion Technology. All right reserved.