Optimizing Turbogenerators for Hybrid-Electric Applications

Abstract

Advancements in distributed electric propulsion have given rise to a wide array of new eVTOL designs featuring tilt rotors, tilt wings and ducted fans. All of these systems pose a common challenge, meeting the electrical power demands of the propulsors. Hybrid-electric drives which combine an engine driven generator with batteries are being pursued to address the range and payload limitations of all electric drives using only batteries. The hybrid systems currently being considered rely on traditional gasoline, diesel, and turbine engines. Gas turbines offer exceptional energy density but are less fuel efficient than piston engines. Two technologies, heat recovery and power transfer, can be incorporated into the gas turbine to significantly improve fuel efficiency. New Centerline Design has conducted parametric trade studies on eVTOL aircraft with turbine based hybrid-electric systems to quantify the benefits that heat recovery and power transfer will have on eVTOL payload and range. The results of this study show that heat recovered gas turbines with power transfer are excellent candidates for next generation eVTOL hybrid-electric propulsion systems.