Quantitative Hypersonic Flow Measurements using Planar Laser-Induced Fluorescence
Date
2018-09-10
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Abstract
The present work focuses on the development, testing, and assessment of several new quantitative analysis methods for nitric oxide planar laser-induced fluorescence experiments. The methods are based on performing a spectral scan with a pulsed laser, exciting multiple nitric oxide transitions,and analyzing the resulting spectra. The nitric oxide fluorescence spectra is processed using the developed quantitative analysis methods to produce temperature, mole fraction and heat flux. The temperature measurement is based on fitting a fluorescence model to the spectra from multiple transitions. The mole fraction measurement uses the fluorescence signal combined with the principle of conservation of mass. The heat flux measurement uses the principle of conservation of energy combined with temperature and velocimetry measurements. To assess these methods, experiments were performed at NASA Langley’s 31-in. Mach 10 wind tunnel, in Hampton Virginia, USA.A nitric oxide planar laser-induced fluorescence experiment investigating a hypersonic boundary layer was performed. The boundary layer was seeded with nitric oxide through a slot located nearthe leading edge. A pulsed laser was directed into the boundary layer from above, exciting the nitric oxide, and spectrally scanning across six fluorescence transitions. The data received from this experiment were processed using the quantitative analysis methods developed, to produce temperature, mole fraction and heat flux measurements. To assess the accuracy of the present methods,each quantitative measurement was compared to computational fluid dynamics (CFD) simulation results. Temperature measurements agreed with CFD predictions within 3-7% in most regions of the boundary layer. Mole fraction measurements agreed with CFD predictions within 6-10%and the heat flux measurement was approximately 26% lower than CFD results. Finally, important experimental design considerations are discussed to enhance these analysis methods in future applications. Overall, nitric oxide planar laser-induced fluorescence measurement methods are demonstrated and applied to a hypersonic boundary layer in a Mach 10 flow, with good agreement when compared to CFD results.
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Fluorescence
Citation
McDougall, C. C. (2018). Quantitative Hypersonic Flow Measurements using Planar Laser-Induced Fluorescence (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/32917