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Description:
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The present work examines line measurements of pressure , temperature , and
density in high speed , non -isobaric flows emanating from an underexpanded jet nozzle .
Line images of rotational and vibrational Raman spectra are collected for a 8 -mm
linear laser probe , and are combined onto the same EMCCD detector . Combining
the two techniques allows for a single -shot measurement of major species , pressure ,
and temperature in a turbulent non -isobaric environment that is chemically reacting .
Temperature measurements along the laser test section are extracted from the rotational
Raman spectrum , whereas major species densities are measured by examining
the intensities of their respective vibrational Raman lines . Pressure can be calculated
using an equation of state , in every location along the linear laser probe . The technique
feasibility is examined by performing measurements of pressure , temperature
and density in a non -reacting underexpanded air jet where the chemical composition
is constant and known . Future work will extend the technique to chemically reacting
supersonic flows with unknown chemical composition . |