CW dye laser technique for simultaneous, spatially-resolved measurements of temperature, pressure, and velocity of NO in an underexpanded free jet

Conference · Wed Jan 01 04:00:00 EST 1992

OSTI ID:5465989

Di rosa, M D; Chang, A Y; Hanson, R K ^[1]

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1. Stanford University, CA (United States)

Gas dynamic quantities within an underexpanded free jet were measured nonintrusively using a rapid-tuning, CW ring dye laser. A nitrogen jet was seeded with 0.5 percent NO in N2, and the conditions were controlled such that a barrel shock formed. The frequency-doubled output of the dye laser was used to spectrally resolve rotational lines in the NO gamma band near 225 nm. With the rapid-tuning capability, these rotational spectra were acquired at a repetition rate of 4 kHz. Spatial resolution was afforded by monitoring the induced fluorescence via a lens and photomultiplier tube. Modeling the spectrally-resolved features with Voigt profiles permitted simultaneous measurements of NO velocity, rotational temperature, and pressure. Expansion of the jet was assumed to be isentropic, and agreement between measured and expected values was typically better than 10 percent over most of the Mach-number range encountered. At high Mach numbers, the measured rotational temperatures systematically departed from the isentropic temperature distribution. Such a measured departure could be ascribed to the onset of a non-Boltzmann distribution of NO rotational states. 23 refs.

• Research Organization: Stanford Univ., CA (United States)
• OSTI ID: 5465989
• Report Number(s): CONF-920157--; AIAA-Paper--92-0006
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
CHALCOGENIDES
DYE LASERS
EXPANSION
FLUID FLOW
FLUID MECHANICS
GAS FLOW
JETS
LASERS
LIQUID LASERS
MEASURING METHODS
MECHANICS
MONITORING
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
PRESSURE MEASUREMENT
RESOLUTION
SHOCK WAVES
SPATIAL RESOLUTION
TEMPERATURE MEASUREMENT
VELOCITY