Hybrid Electric Aircraft Propulsion System Design Analysis and Simulation Tool Development

Abstract

As climate change becomes an ever-important issue, the aviation industry is looking to eliminate its emissions in the coming generations of aircraft. To make this happen faster, electrified propulsion systems must be designed and analyzed quickly and accurately. Design software and simulation tools tailored to hybrid electric aircraft play an important role in the accuracy and speed of these processes. This paper reviews design methods and software packages for hybrid electric propulsion system design, as well as discusses the modification of modeling and simulation tools for performance analysis. An initial cruise analysis was done using a Matlab script to assess the performance of an aircraft over a wide range of degree of hybridizations (DOH), take off weights, and propulsion component sizes. This analysis narrowed the design range to a DOH of 0-.2, an engine mass fraction of .2-.23, and a maximum takeoff weight of about 4000 lbs. This narrowed design range was then applied to an existing Matlab and Simulink tool on a unique aircraft design to simulate a hybrid turbo-electric aircraft flying a common mission profile. This tool was modified to output important metrics for analysis such as powertrain component power output, fuel and energy consumption, speed and range, and carbon emissions from energy used. Additionally, errors in the flows and assumptions of the tool were corrected to accurately model the weight and power use of the aircraft. With this revised simulation tool, a full mission was simulated for the example aircraft. Battery voltage and capacity, component power output, fuel and electricity use, aircraft mass, and speed and range were all analyzed and used to make design recommendations for the unique 2-passenger general aviation aircraft with a mission range of ~300 nautical miles.