Date of Award

Fall 12-15-2022

Access Type

Thesis - Open Access

Degree Name

Master of Science in Aerospace Engineering

Department

Aerospace Engineering

Committee Chair

Richard P. Anderson

Committee Co-Chair

Kyle B. Collins

Committee Advisor

Anastasios S. Lyrintzis

College Dean

James W. Gregory

Abstract

In the emerging market of Advanced Air Mobility (AAM), aerospace companies have been designing and prototyping electric and hybrid vehicles to revolutionize travel. These vehicles must have low noise and particulate emissions while also having enough propulsive efficiency to complete the mission. This thesis aims to study the relationship between noise and propulsive efficiency as related to any aircraft equipped with an electric motor and a variable pitch rotor/propeller. The combination of the electric motor with the variable pitch propeller/rotor allows for a decoupled rotational speed and torque generation, meaning that the electric motor can generate the same amount of torque while operating at different rotational speeds. This feature allows the rotor/propeller to hold constant thrust at different combinations of rotational speeds and torque, by adjusting the collective pitch of the blades. This research will show that, for a rotor at constant thrust, the minimum noise (from loading and thickness contributions) and minimum power operating points in terms of rotor RPM and collective blade pitch, are not the same thus leading to the fact that it takes increased energy to decrease noise. A MATLAB code is developed to investigate the power and noise relationship by employing several functions to integrate XFOIL and Blade Element Momentum Theory for the rotor performance calculations and WOPWOP for thickness and loading noise analysis. Broadband noise is not included in the analysis herein. In addition, this thesis will present the design and build of a rotor test stand used to test rotors to validate the simulation results and provide hardware-based solutions for the power required by a rotor in hover. Based on the experimental and simulation results, a closed form equation is also proposed that shows the power required for a rotor at constant thrust, and it can be included in a preliminary rotor performance analysis for AAM vehicle design.

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