Reconfiguring the CAT250TJ micro turbojet engine for shaft power output

Micro turbojet and micro turboprop engines have been investigated as alternative powerplants for UAVs and similar applications. The conversion of the CAT250TJ micro turbojet engine into a power turbine configuration is presented in this study. In the manufactured design, the jet pipe is replaced by an inter-turbine duct and a single-stage power turbine. Simple rectangular exhaust ducts are incorporated downstream of the power turbine. Performance evaluation is conducted by means of 1D Flownex ® models based on CFD-generated compressor and turbine maps. The numerical results are validated by means of cold and hot experimental tests. The experimental results provide good correlation with the Flownex ® models. The Flownex ® simulation results indicate that the manufactured power turbine can produce the design shaft power output of 37.8 kW at 60 000 r/min while powered by the CAT250TJ engine.