ORCID

johnppatten7@gmail.com

Keywords

Solid Fuel, Ramjet, Scramjet, Additive Manufacturing, Airbreathing Propulsion

Abstract

Solid fuels have primarily been investigated in the context of non-airbreathing systems such as hybrid rockets and solid rocket boosters. In both cases, the vehicle must carry an oxidizer— either as gaseous or liquid oxygen in hybrid rockets or embedded within the fuel grain in solid rocket boosters. Airbreathing engines, such as ramjets and scramjets, offer a distinct advantage over these technologies by extracting the necessary oxygen for combustion from the surrounding atmosphere, greatly increasing range. Solid fuels are optimal for many ramjet and scramjet applications due to their high volumetric energy density and long shelf life compared to liquid and gaseous fuels. However, operating these engines at high altitudes presents challenges due to low pressure, which leads to ignition difficulties and blowout. To implement these technologies, advanced fuel formulations with wider flammability limits are necessary. Additive manufacturing offers unparalleled flexibility in constructing solid fuel grains, providing precise control over geometry and internal composition compared to traditional casting methods. This paper examines the potential of additively manufactured solid fuels—PLA, PETG, ABS, and PMMA—for use in ramjets and scramjets, characterizing key performance parameters such as specific impulse, combustion efficiency, and regression rate. Fuels were tested under realistic ramjet and scramjet flight conditions in multiple engine configurations, including an optically accessible small-scale ramjet and scramjet, as well as a full-scale, axially symmetric ramjet.

Completion Date

2025

Semester

Spring

Committee Chair

Ahmed, Kareem

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Identifier

DP0029369

Document Type

Dissertation/Thesis

Campus Location

Orlando (Main) Campus

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