Experimental development and performance investigation of a self-consuming, hybrid autophage rocket propulsion system

Bzdyk, Krzysztof W. (2024) Experimental development and performance investigation of a self-consuming, hybrid autophage rocket propulsion system. PhD thesis, University of Glasgow.

Abstract

The hybrid autophage engine concept, or self-eating rocket, is an emerging rocket engine technology which aims to greatly reduce launch vehicle dry mass over conventional propulsion systems and allow for the miniaturization of launch vehicles for small satellite payloads. This is achieved by replacing the fuselage of a conventional bi-propellant launch vehicle with a polymer material. By using the heat from the combustion chamber, the fuselage may be vaporized and combined with liquid fuel and oxidiser drawn from the diminishing propellant tanks such that the structural mass of the rocket decreases throughout the launch and contributes toward the total propellant mass flow rate. This greatly increases the efficiency of the rocket allowing for smaller launch vehicles to deliver a payload to low earth orbit.

This study was an investigation in the design and test of a novel hybrid autophage engine system to evaluate the feasibility of the concept, identify key parameters that influence autophage engine performance, and form a performance baseline to anchor computational models for future development. The project consisted of three engines (Ouroboros-1, 2, 3) which were iteratively designed and tested in various configurations.

Ouroboros-1 and Ouroboros-2 were operated as bi-propellant engines which served as prototyping platforms and performance baselines for the Ouroboros-3 autophage engine. All bi-propellant tests were conducted in a steady state operating mode; while autophage tests were conducted in both steady state and pulsed operating modes. Additionally, both the bi-propellant and autophage tests were operated across a range of mixture ratios and engine inlet conditions to characterise engine performance over a wide operating box.

A performance analysis was conducted on the resulting experimental data to compare to theoretical performance of a chemical equilibrium model. Further analysis of the engines evaluated the influence of combustion chamber temperature, throttle setting and mixture ratio on the autophage contribution to both total fuel mass flow rate and total propellant mass flow rate. Additionally, frequency analyses investigated the influence of the autophage engine design on the formation of combustion instabilities.

When compared to bi-propellant operation, the fuselage was recorded as contributing between 5.1% to 15.7% of the total propellant mass during steady state operation and 0% to 18.6% when operating in pulsed mode. These results envelope typical values for the structural mass fraction of conventional launch vehicles and support the feasibility of autophage engines for larger scale development.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Supported by funding from the Defense and Security Accelerator (DASA) operated by the Defense Science and Technology Laboratory (DSTL) of the UK Ministry of Defense, and the Impact Acceleration Account of the Science and Technology Facilities Council (STFC)
• Subjects: T Technology > TL Motor vehicles. Aeronautics. Astronautics
• Colleges/Schools: College of Science and Engineering > School of Engineering
• Funder's Name: Science & Technologies Facilities Council (STFC)
• Supervisor's Name: Harkness, Professor Patrick
• Date of Award: 2024
• Depositing User: Theses Team
• Unique ID: glathesis:2024-84776
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 06 Jan 2025 12:08
• Last Modified: 06 Jan 2025 12:08
• Thesis DOI: 10.5525/gla.thesis.84776
• URI: https://theses.gla.ac.uk/id/eprint/84776

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