Applications of absorption spectroscopy to the study of hypersonic flow conditions in ground test facilities
- The hypersonic flight regime is a hostile one, characterized by significant thermal loading on vehicle structures. In order to fortify vehicle platforms and mission architectures employing these high speeds, experimental testing is crucial to better characterize the thermochemical processes prevalent behind the strong shock waves emblematic of hypersonic flight. As part of this effort, ground test facilities fulfill an important niche. These facilities simulate realistic hypersonic flight environments by generating high-speed, high-enthalpy flows in controlled environments. In this dissertation, laser absorption spectroscopy is leveraged to study several different hypersonic flows or relevant high-temperature conditions in three different types of ground test facilities. Spectroscopic targets include nitric oxide (NO), atomic nitrogen (N), atomic oxygen (O), molecular nitrogen (N2), and carbon monoxide (CO). The monitoring of these species permits the assessment of hypersonic-relevant phenomena, including chemical non-equilibrium, vibrational freezing, and electronic excitation. Three major experimental efforts underlie this dissertation. The first is the characterization of the hypersonic flows in the Caltech T5 Reflected Shock Tunnel. Spectroscopic measurements allowed for the determination of freestream temperature, composition, and flow velocity. These measurements were then extended into near-body flows behind the shock waves generated by cylinder and wedge test articles. The second study is the characterization of the NASA Ames Interaction Heating Facility (IHF), a 60 MW Arcjet used to study thermal protection systems (TPS). Spectroscopic investigation targets the determination of stagnation enthalpy, a crucial operational parameter. Finally, the third study utilizes an in-house Stanford shock tube to investigate nitrogen-chemistry electronic excitation and ionization, high-temperature processes relevant to lunar return trajectories.
|Type of resource
|electronic resource; remote; computer; online resource
|1 online resource.
|Finch, Peter Martin
|Degree committee member
|Degree committee member
|Stanford University, School of Engineering
|Stanford University, Department of Mechanical Engineering
|Statement of responsibility
|Submitted to the Department of Mechanical Engineering.
|Thesis Ph.D. Stanford University 2023.
- © 2023 by Peter Martin Finch
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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