Energy and configuration management strategy for battery/fuel cell/jet engine hybrid propulsion and power systems on aircraft

Abstract

Hybridization of power sources by combining their performance advantages and balancing disadvantages is becoming a feasible solution during the process of designing electricity propulsion systems on aircraft. Novel hybrid propulsion and power (HPP) systems combining batteries, fuel cells, jet engines are proposed in this paper, which can respectively provide high thrust and low thrust specific fuel consumption in the take-off and cruise segment. The mathematical models are built and the main parts are validated to determine the performance and size parameters of these components. The main conclusions are as follows: (1) Under the cruise segment, the reduction rate of fuel cell weight slows with decreasing fuel utilization. Meanwhile, the thrust and thrust specific fuel consumption are both increased. These values of 4 kN and 15.32 g/s/kN are reached to achieve the endurance of 19.6 hours. (2) The speed characteristic of the HPP system is complicated, but the thrust of the system is almost only affected by air mass flow with varying altitudes. It can vary from 100% to about 50% by adjusting the fuel flow rate in the afterburner. (3) The flight envelop of the aircraft are limited by the thrust/drag balance and fuel cell operating temperature. The highest operating altitude is about 27.5 km, with a maximum working Mach number of 1.8. (4) The weight ratios of the fuel cell, motor, battery, and fuel loaded are 15%, 12%, 8%, and 56%. Most of the fuel (89%) is consumed in the cruise segment.