Laser ion time-of-flight velocity measurements using N2(+) tracers
Abstract
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 mu s, 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.
- Publication:
-
AIAA Journal
- Pub Date:
- February 1995
- DOI:
- 10.2514/3.12417
- Bibcode:
- 1995AIAAJ..33..296R
- Keywords:
-
- Flow Measurement;
- Flow Velocity;
- Ion Probes;
- Laser Applications;
- Nitrogen Ions;
- Velocity Measurement;
- Air Flow;
- Flames;
- Neodymium Lasers;
- Yag Lasers;
- Instrumentation and Photography