The authors report measurements of pressure, temperature, and velocity in an underexpanded jet using planar laserinduced fluorescence of nitric oxide. Ultraviolet transitions near 44097.5 cm(exp-1) in the A-X (0,0) system of nitric oxide were excited using narrow linewidth laser radiation generated from an optical parametric system, injection seeded using a distributed feedback diode laser. Planar laser-induced fluorescence images with excellent spatial resolution and signal-to-noise ratio were acquired by tuning the frequency of the laser radiation over the nitric oxide absorption line. The images were corrected on a shot-to-shot basis for fluctuations in the laser spatial profile. Line shapes constructed from the corrected planar laser-induced fluorescence images were used to determine pressure and temperature values along the centerline of the jet. Good agreement between laser-induced fluorescence and previously reported N2 coherent anti-Stokes Raman scattering measurements was observed. The laser-induced fluorescence measurements also compared well with calculations of pressure and temperature using computational fluid dynamics codes. Velocity was measured in supersonic regions ofthe flowfield on the basis ofthe Doppler shift in the nitric oxide absorption lines. Planar laser-induced fluorescence images were acquired using laser sheets propagating at 90 and 45 degrees with respect to the flow direction; velocity was determined from the frequency shift of the absorption lines for these two shifts. The laser-induced fluorescence technique can potentially be applied to obtain instantaneous measurements of thermodynamic properties and multiple velocity components in high-speed turbulent flows.
Pressure, temperature, and velocity measurements in underexpanded jets using laser-induced fluorescence imaging
Druck-, Temperatur- und Geschwindigkeitsmessungen in unterexpandierten Jets mit Hilfe der Laser-induzierten Fluoreszenzabbildung
AIAA Journal ; 47 , 4 ; 839-849
2009
11 Seiten, 10 Bilder, 43 Quellen
Aufsatz (Zeitschrift)
Englisch
Düsenströmung , Fluoreszenzmessung , bildgebendes Verfahren , laserinduzierte Fluoreszenz , Druckverteilung , Temperaturverteilung , Geschwindigkeitsverteilung , kohärente Antistokes-Raman-Streuung , Vergleichsanalyse , Strömungslehre , Überschallströmung , Doppler-Verschiebung , Stickstoffoxid , Absorptionslinie , turbulente Strömung , thermodynamische Eigenschaft
Fluorescence Imaging Study of Impinging Underexpanded Jets
British Library Conference Proceedings | 2008
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