Design and Initial Operational Characteristics of a Shock Tube-Raman Scattering Calibration System
Final rept. 1 Oct 1981-30 Sep 1982
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN
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A shock tube system has been designed and constructed to provide a high-temperature, local thermal equilibrium gas sample for the determination of Raman scattering cross sections. The shock tube was designed for operation over the temperature T range of 800 or T or 4000 K and the number density n range of 0.2 or n or 2.1 amagat. The fabricated steel shock tube was 6.98 m long with a 6.35-cm inner diameter the drivendriver section length ratio was 1.88. The initial demonstration of a laser Raman-shock tube system for high-temperature cross section and calibration measurements was accomplished. The incident Mach number range of 4 to 5 was studied with the driver gas and N2 as the driven species using a seamless shock tube and the same tube which was retrofitted with a stainless steel tube liner. The Raman spectra obtained with the seamless steel tube revealed effects of rust particles which has been scrubbed from the tube wall. Upon insertion of the stainless steel liner, these effects were reduced to small corrections to the Raman signal. Vibrational Raman spectra of shock-heated N2 were acquired using a frequency-doubled ruby laser, spectrometer dispersion, and a single PMT detection channel.
- Test Facilities, Equipment and Methods
- Fluid Mechanics
- Atomic and Molecular Physics and Spectroscopy