Accession Number : AD0466305

Title :   SOME MEASUREMENTS OF ROTATIONAL TEMPERATURES IN A LOW DENSITY WIND TUNNEL USING ELECTRON BEAM FLUORESCENCE.

Descriptive Note : Technical rept.,

Corporate Author : CALIFORNIA UNIV BERKELEY INST OF ENGINEERING RESEARCH

Personal Author(s) : Robben, F. ; Talbot, L.

Report Date : MAY 1965

Pagination or Media Count : 1

Abstract : The fluorescence of a 30 kV electron beam has been used as a probe to measure the rotational distribution function of flowing nitrogen in a low density wind tunnel. The fluorescence consists predominantly of the so-called first negative system of nitrogen. Measurements of the intensities of the rotational structure of the (0-0) vibrational band have been used to calculate, through a theoretical model, the original rotational distribution function of N2 before excitation. A series of measurements was performed in the undisturbed flows of subsonic nozzle, a Mach 4 noizle, and free jet expansions from sonic orifices at Mach numbers ranging up to 19. The rotational temperature measurements are shown to be about 3% high at 280 K, with a progressively increasing error at lower temperatures. These measurements also indicated no measurable lag in rotational temperature in the free jet expansion. (Author)

Descriptors :   (*FLUID MECHANICS, DYNAMICS), (*ELECTRON BEAMS, FLUORESCENCE), MEASUREMENT, NITROGEN, GAS FLOW, VORTICES, EXCITATION, SUBSONIC FLOW, SUPERSONIC FLOW, NOZZLE FLOW, JETS, TEMPERATURE, LIGHT, INTENSITY, PHOTOMULTIPLIER TUBES, GROUND STATE.

Distribution Statement : APPROVED FOR PUBLIC RELEASE