A laser ion time-of-flight technique for velocity measurements using N2(+) tracers has been demonstrated. The ions are formed by a multiphoton interaction with the third harmonic of a Nd:YAG laser and are detected by a negatively biased ion probe. In air flows with positive probe bias, negative ions, possibly O2(-) formed by attachment with free electrons, were detected and could also be used as tracers. The lifetime of the ions is controlled by charge recombination. At atmospheric conditions and after a delay of 600 microseconds, ion signal was still above background noise level. Measurements of flow velocities in both a low-speed freejet and in the flame of a propane-air torch are presented. Reduced flight time in high-speed flows can produce even higher signals.
Laser ion time-of-flight velocity measurements using N(2+) tracers
Strömungsmessung am und im Brenner mittels Laser-Ionen Zeitmessungen mit Stickstoffdioxidindikatoren
AIAA Journal ; 33 , 2 ; 296-301
1995
8 Seiten, 8 Bilder, 22 Quellen
Article (Journal)
English
Laser Ion Time-of-Flight Velocity Measurements Using N2+ Tracers
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