Flow diagnostics of an arcjet using laser-induced fluorescenceA diagnostic has been developed to measure velocity and translational temperature in the plume of an arcjet thruster. Laser induced fluorescence with a narrowband CW laser is used to probe the Balmer alpha transition of excited atomic hydrogen. The velocity is determined from the Doppler shift of the fluorescence excitation spectrum while temperature is inferred from its shape. Analysis shows that while Doppler broadening is the only significant broadening mechanism, the fine structure of the transition must be accounted for. Near the exit plane, axial velocities vary from 4 to 14 km/s; radial velocities vary from 0 to 4 km/s; and swirl velocities are shown to be relatively small. Temperatures from 1000 to 5000 K indicate high dissociation fractions.
Document ID
19920066219
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Liebeskind, John G. (NASA Lewis Research Center Cleveland, OH, United States)
Hanson, Ronald K. (NASA Lewis Research Center Cleveland, OH, United States)
Cappelli, Mark A. (Stanford University CA, United States)