Modeling and Performance Analysis of a Turbojet Hybrid Electric Propulsion System

Reducing the fuel consumption, noise and pollution and increasing flight altitude are very important issues for an air vehicle. One solution to achieve these important features is the combination of the powers obtained from internal combustion engines and electric motors to generate propulsion. In the development of this type of propulsion systems, uncomplicated structure, low implementation cost and limited weight are effective factors for practicality. In this research, a partial turboelectric hybrid propulsion system for small unmanned aerial vehicles has been conceptually designed. For this purpose, about 20 % of the turbine power of a small turbojet engine is dedicated to providing the electrical power of the electric propulsion unit. This power is used to rotate a ducted fan by an electric motor and produce a separate thrust in addition to the turbine engine thrust. The modeling results show a 34% improvement in the specific fuel consumption and a 44 % increase in the thrust value of the hybrid engine compared to the baseline turbojet engine in ground test conditions.