Thermodynamic performance evaluation of a turbine-less jet engine integrated with solid oxide fuel cells for unmanned aerial vehicles

The performance of conventional turbine engines for unmanned aerial vehicles (UAVs) is limited by the combustor exit temperature and the concept of turbine-less jet engines was proposed. For the engine, compressors are powered by a battery in the current study. The endurance and thrust-weight ratio of UAVs equipped with the turbine-less jet engines are strongly affected by the performance of batteries. In order to improve the performance of UAVs, the feasible scheme of turbine-less jet engines integrated with a solid oxide fuel cell (TLFC engine) is put forward. For the TLFC engine, reformed gas is provided to the solid oxide fuel cell (SOFC). The SOFC produces electric power to drive the compressor by a motor. Then, the extra fuel and SOFC exhaust enter into the combustor. The combustor exhaust expands and produces propulsion power in the nozzle. In order to evaluate the performance of the TLFC engine, the thermodynamic analysis model is built. The effects of pressure ratios, combustor exit temperature, flight Mach number and flight altitude on the TLFC engine are studied. The preliminary results are as follows. The TLFC engine has obvious advantages over the traditional turbojet engine in specific thrust and specific impulse. The increment of the specific thrust ranges from 27% to 55%. The maximum pressure ratio and Mach number are 33 and 0.89, respectively.