Publication Date

2025

Document Type

Thesis

Committee Members

Mitch Wolff, Ph.D. (Advisor); Timothy Ombrello, Ph.D. (Committee Member); Katherine Opacich, Ph.D. (Committee Member)

Degree Name

Master of Science in Mechanical Engineering (MSME)

Abstract

A study was completed on the application of mid-wave infrared (MW-IR) imaging for diagnostics in supersonic combustion exhaust flows, with the objective of enhancing optical access and measurement accuracy. Other optical based techniques of thermography require complicated setups and analysis to determine the temperature of a flow with high accuracy, where MW-IR is a more simplistic "point and shoot" technique. The simplicity of MW-IR comes with the trade off of gaining simplicity but adding uncertainty into the measurements. The MW-IR camera was positioned to view the exhaust of the combustor to provide an unobstructed view of the flow, addressing limitations in past studies where windowed setups restricted long-wavelength emissions from CO and CO2. By calibrating the MW-IR imaging system and implementing a shock detection algorithm, the study accurately captured radiance data across multiple spectral bands, providing a direct measure of the radiance from the combustion species concentrations and temperature within the exhaust flow. Utilizing a combination of radiance-to-temperature conversion methods, including Radcal 2.0, EES Gas Emittance, Gray Gas Emissivities, and the Radis line-by-line solver, the temperature profiles were derived for quasi-steady combustion conditions for varied fuel flow rates. The results demonstrate the MW-IR imaging approach as a viable method for obtaining spatially resolved temperature data in high-speed combustion exhausts, offering significant insights for future developments in high-speed air-breathing propulsion diagnostics.

Page Count

101

Department or Program

Department of Mechanical and Materials Engineering

Year Degree Awarded

2025

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