Vibrational relaxation measurements in an expanding flow using spontaneous Raman scattering

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Journal of Thermophysics and Heat Transfer; (United States)

DOI:https://doi.org/10.2514/3.479· OSTI ID:6979800

Sharma, S P; Ruffin, S M; Gillespie, W D; Meyer, S A ^[1]

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1. NASA-Ames Research Center, Moffett Field, CA (United States)

Vibrational relaxation of nitrogen in a two-dimensional nozzle flow is studied with spontaneous Raman scattering. An electric arc-driven shock tube operating as a reflected shock tunnel produces stagnation conditions of 5600 K and 100 atm. A 248-nm KrF laser pulse is focused into the nozzle to produce spatially resolved spontaneous Raman spectra. Vibrational population distributions are derived from the spectra for the states v = 0 to v = 8. The experimental results are compared with two theoretical models: (1) the Landau-Teller relaxation model and (2) a numerical solution of the master equations using transition rates derived from Schwartz, Slawsky and Herzfeld (SSH) theory. We have measured a value for the Landau-Teller correction factor (phi) to be 1.0-1.5. 13 refs.

• Research Organization: National Aeronautics and Space Administration, Moffett Field, CA (United States). Ames Research Center
• OSTI ID: 6979800
• Journal Information: Journal of Thermophysics and Heat Transfer; (United States), Journal Name: Journal of Thermophysics and Heat Transfer; (United States) Vol. 7:4; ISSN 0887-8722; ISSN JTHTEO
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
FLUID FLOW
GAS FLOW
MATHEMATICAL MODELS
NOZZLES
RAMAN SPECTRA
SHOCK TUBES
SPECTRA
TWO-DIMENSIONAL CALCULATIONS