Multiscalar line measurements in nonisobaric high-pressure underexpanded supersonic jets using rotational-vibrational raman spectroscopy

摘要

This work describes the development of a Raman spectroscopy system formeasuring aerothermochemistry in high-speed jets and flames. A transmissive gratingspectrometer was newly developed for capturing pure rotational Raman and rotationalvibrationalRaman with a single CCD camera. Previous state-of-the-art experimentsapplied line imagining in known flowfields of constant pressure. The system describedherein is designed to provide local measurement of pressure, with full thermochemistry,along a line. In every point, temperature will be measured by examining the Boltzmanndecay of the rotational spectrum, while molar fraction will be measured from thevibrational Raman spectrum. The temperature and concentrations will then be combinedto obtain partial pressure measurements via the equation of state. This work examinesthe phenomenology of rotational and vibrational Raman scattering and proposesalgorithms that can be used for data extraction.