gatech ece phd defense

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Graduate Education

Office of graduate and postdoctoral education, phd defense by chrysoula lydia pastra, december 4, 2024.

Chrysoula Lydia Pastra

(Advisor: Prof. Dimitri Mavris)

will defend a doctoral thesis entitled,

Methodology formulation for multi-energy sustainable turboprop regional aircraft sizing with airport infrastructure capability constraints

 Wednesday, December 4th at 8:00 a.m. EST

Online:  Click here to join the meeting , or

CoVE,  

Weber Space Science and Technology Building (SST II)  

With climate change being a more prominent issue in our society, every industry is moving towards more sustainable solutions. The aviation industry has set forth certain goals that it needs to reach to reduce if not eliminate harmful emissions. The aviation industry has been focused on exploring the feasibility and viability of different technological solutions to minimize greenhouse gas emissions, with electrification and hydrogen usage being at the epicenter. Infrastructure and regulation changes are two missing pieces of the puzzle. Technology, infrastructure, and regulations are three pillars that need to be considered simultaneously to accurately evaluate the feasibility of shifting towards a net zero aviation reality in the future. All of these pillars are crucial aspects, and without one, the shift cannot occur.

Current state-of-the-art research focuses on technological solutions and their feasibility. Technological solutions such as hybrid electric aircraft, fully electric aircraft, hydrogen-powered aircraft, and sustainable aviation fuels are all evaluated. Researchers perform sizing and synthesis analysis for the new propulsive methods to evaluate the effects on Green House Gases by applying mission and performance constraints, while the infrastructure aspect is evaluated separately. Analysis of what will be required to support the new generation green aircraft is performed such as charging stations, hydrogen hydrants and pipelines, and charging schedule optimizations. The major identified gap in the literature and current research is that the infrastructure needs are not considered as constraints in aircraft sizing and synthesis research. Infrastructure poses a major obstacle to overcome in the transition towards a green aviation reality. Similarly, regulations and incentives have been previously identified but they have not been evaluated in conjunction with infrastructure and design. Additionally, with the variety of technological solutions available, there is an inherent uncertainty on which path different stakeholders will follow, causing further stagnation in infrastructure development. Using the automotive industry as a thought experiment, this thesis will explore these identified gaps.

The methodology that is proposed within this thesis stems from the realization that these technologies that have been proposed and evaluated in previous research cannot be implemented unless there is a drastic change in infrastructure or infrastructure and technologies are considered as two pieces of the same puzzle and evaluated together. This thesis will be composed of three experiments that will tie together the technology and infrastructure, and in the future can be expanded to also include the third pillar: regulations. The first aspect of this thesis tackles the lack of research that is done on multi-energy source regional aircraft. Although there has been research done on smaller aircraft and UAVs using both hydrogen fuel cells, and batteries for an energy-sharing topology, detailed trades and sizing evaluations have been lacking. The first experiment aims to show that an energy-sharing aircraft can provide significantly higher fuel savings than either a purely hybrid electric or hybrid hydrogen fuel cell-powered aircraft. The second experiment will be directly using the optimized multi-energy source aircraft to explore the fleet level impact within the US regional routes and compare those to the purely electric, and evaluate different introduction strategies. Finally, where the new methodology comes into place in the third experiment. Within this experiment, the optimized aircraft that was sized with traditional sizing and synthesis methods will be evaluated with infrastructure and operational constraints. The new design space will then be evaluated, and different scenarios will be performed to identify how the infrastructure and operational constraints need to be changed in order to allow for the shift towards greener new-generation aircraft. This new design space will allow for constrained optimization and will generate a new optimized aircraft design which is hypothesized to be significantly different than the aircraft produced in experiment 1. This methodology will allow future researchers to evaluate new types of technologies in a more holistic way as the current state of the market can also be considered within the sizing and optimization of the aircraft.

• Prof. Dimitri Mavris – School of Aerospace Engineering (advisor)
• Prof. Brian German – School of Aerospace Engineering
• Prof. Daniel Schrage– School of Aerospace Engineering
• Dr.  Pfaender Holger – School of Aerospace Engineering
• Dr. Eric Upton – Gulfstream Aerospace

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Daniel Guggenheim School of Aerospace Engineering

College of engineering, doctoral proposal & defense.

Doctoral Proposal

About a year after passing the qualifying exams, you should work with your advisor to select a proposal review committee and set a thesis proposal date. The following guidelines should be followed:

• The proposal review committee must include at least three subject matter experts, one of whom is the student's faculty advisor and the majority of whom are from Georgia Tech AE. At least one member must be from outside Georgia Tech AE;
• The thesis proposal establishes a structure of mutual expectations between the advisor and student. The plan is subject to change to accommodate new findings;
• The proposal should be no longer than 30 pages and must include an explanation of the research's contribution to the discipline, a literature review, early results, and an overview of next steps;
• Students should expect to have their proposal critiqued as a way of sharpening the focus of their doctoral research plan;
• There must be at least a six (6) month lag between the proposal and the defense: time for the student to implement suggested improvements and seek ongoing guidance from the advisor and/or committee;

Doctoral Defense

About six months after you have submitted a successful proposal, you will be expected to schedule a thesis defense. The doctoral defense committee should include at least five (5) subject matter experts, the majority of whom are from Georgia Tech AE, and one of whom is not from Georgia Tech AE.

• Most doctoral defense committees are similarly composed to the proposal committee;
• The student is responsible for scheduling the defense place and date;
• Doctoral defenses are publicly advertised and attended, and involve a 50-minute presentation, after which questions from the public, and, then from the committee will be fielded;
• After privately deliberating and voting, the defense committee will render a decision on the granting of the doctoral degree.