Design and analysis of a compact high-speed air-breathing engine

Kato, Nozomu

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https://hdl.handle.net/2142/130160 Copy

Description

Title

Design and analysis of a compact high-speed air-breathing engine

Author(s)

Kato, Nozomu

Issue Date

2025-07-10

Director of Research (if dissertation) or Advisor (if thesis)

• Lee, Tonghun
• Mayhew, Eric K

Doctoral Committee Chair(s)

Lee, Tonghun

Committee Member(s)

• Rovey, Joshua L
• Chamorro, Leonardo P

Department of Study

Mechanical Sci & Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Scramjet
• Ramjet
• Air-Breathing Engine
• Hypersonics

Abstract

This dissertation investigates the underlying physics of challenges associated with compact, high-speed, air-breathing propulsion systems and examines potential solutions. The primary focus is on the unique technical challenges posed by the stringent requirement for a compact design, which will fundamentally alter system performance. Such propulsion systems are critical for the development of platforms such as the Air-Launched Effect (ALE)—a small, unmanned reconnaissance aircraft. To address these challenges, this study combines component design, theoretical analysis, high-speed wind tunnel experiments, and reduced-order modeling. Component-level analyses revealed critical design trade-offs. For the inlet, it was found that while scoop inlets offered high theoretical efficiency, truncated planar two-dimensional inlets provided superior performance for compact designs. For the combustor, experiments demonstrated that newly designed inserts, particularly mesh-based inserts, were capable of achieving stable and more compact combustion compared to a baseline configuration. For the exhaust nozzle, analysis showed that designing for under-expanded conditions enabled a remarkable 44 % length reduction with a corresponding thrust penalty of 20 %. Subsequently, these component-level findings were integrated into a reduced-order model. After its combustor sub-model was tuned and validated against the experimental data, the complete model was used to produce a preliminary integrated engine design, 1319.2 mm in length, capable of generating 137.8 N of thrust for the target flight condition. The primary contribution of this work is a complete design-and-analysis framework that provides critical insights into the performance of compact ramjet/scramjet components and delivers a validated tool for the rapid preliminary design of such propulsion systems.

Graduation Semester

2025-08

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/130160

Copyright and License Information

Copyright 2025 Nozomu Kato

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