ORCID

0009-0008-2038-9224

Keywords

Hypersonic wind tunnel flow characterization, Vitiated air, Effective specific-heat ratio, Thermochemical nonequilibrium, Schlieren flow diagnostics, Pitot-rake measurements

Subject Categories

Aerodynamics and Fluid Mechanics | Aerospace Engineering | Thermodynamics

Abstract

Reliable interpretation of hypersonic ground-test data requires knowledge of the thermochemical state delivered to the test section, especially in combustion-heated facilities where the gas is chemically altered before nozzle expansion. This thesis investigates the HyperReact vitiated hypersonic wind tunnel using the effective specific-heat ratio, γeff, as an experimentally inferred indicator of the coupled chemical and gas-dynamic behavior of hydrogen-air vitiated flow. HyperReact produces high stagnation temperatures through hydrogen-air combustion before expanding the mixture through interchangeable converging-diverging nozzles. During this expansion, temperature-dependent specific heats, molecular-weight changes, finite-rate chemistry, and internal energy relaxation can modify the relationship between Mach number, pressure ratio, and speed of sound. The delivered flow state was reconstructed using synchronized schlieren imaging, wall static pressure, plenum pressure and temperature, and pitot-rake measurements. Schlieren Mach-angle measurements were paired with pressure ratios to infer Mach number and γeff, while rake measurements provided spatially distributed reconstructions across the sampled core flow. Results were compared with Cantera-based thermochemical predictions. The Mach 2.82 schlieren results produced angles close to prediction, but γeff was strongly affected by pressure-ratio sensitivity. The Mach 4.17 schlieren results suggested finite-strength wave behavior rather than an ideal Machwave response. Rake reconstructions for the Mach 3.47 and Mach 4.17 nozzles produced physically reasonable Mach numbers and γeff values while revealing spatial nonuniformity in the delivered flow field.

Completion Date

2026

Semester

Summer

Committee Chair

Dr. Kareem Ahmed

Degree

Master of Science in Aerospace Engineering (M.S.A.E.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Format

PDF

Document Type

Thesis

Language

English

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