Measurements were conducted at the University of Virginia Supersonic Combustion Facility of the flow in a constant-area duct downstream of a Mach 2 nozzle. The airflow was heated to approximately 1200 K in the facility heater upstream of the nozzle. Dual-pump coherent anti-Stokes Raman spectroscopy was used to measure the rotational and vibrational temperatures of and at two planes in the duct. The expectation was that the vibrational temperature would be in equilibrium, because most scramjet facilities are vitiated air facilities and are in vibrational equilibrium. However, with a flow of clean air, the vibrational temperature of along a streamline remains approximately constant between the measurement plane and the facility heater, the vibrational temperature of in the duct is about 1000 K, and the rotational temperature is consistent with the isentropic flow. The measurements of vibrational temperature enabled cross-stream nonuniformities in the temperature exiting the facility heater to be documented. The measurements are in agreement with computational fluid dynamics models employing separate lumped vibrational and translational/rotational temperatures. Measurements and computations are also reported for a few percent steam addition to the air. The effect of the steam is to bring the flow to thermal equilibrium, also in agreement with the computational fluid dynamics.
Nonequilibrium Supersonic Freestream Studied Using Coherent Anti-Stokes Raman Spectroscopy
AIAA Journal ; 53 , 9 ; 2762-2770
2015-06-25
9 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Nonequilibrium Supersonic Freestream Studied Using Coherent Anti-Stokes Raman Spectroscopy
Online Contents | 2015
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