Flow velocity measurements in nitrogen plumes stimulated by REMPI

Carl Dankert, Hideo Mori

Research output: Contribution to journalConference article

Abstract

In the DLR-high vacuum plume test facility STG, experiments have been performed to study the expansion of supersonic plumes into vacuum with N 2 as a test gas. The measured values were the Pitot pressure, the molecular number flux, the rotational temperature and the density. The last two quantities were measured by the 2+2 REMPI-technique with a stimulation wavelength of 283-284 nm (REMPI = resonance enhanced multi photon ionization). This method is also suitable to measure the absolute flow velocity by the ion time-of-flight (TOF) method, The apparatus for the combination of the REMPI and TOF technique is similar to that for the TOF experiments using electron beam bombardment, but a focused laser beam is used instead of an electron beam. The results of such laser measurements in highly rarefied plumes for several stagnation temperatures are presented with nitrogen as test gas. On-axis results fit well with the theoretical limiting velocity for perfect expansion; angular velocity profiles off-axis are discussed and compared to theory. This study is focused on the experimental procedure to measure the flow velocity of N2 in rarefied plumes expanding from supersonic nozzles into vacuum.

Original languageEnglish
Pages (from-to)304-308
Number of pages5
JournalICIASF Record, International Congress on Instrumentation in Aerospace Simulation Facilities
Publication statusPublished - Dec 1 2003
EventICIASF '03: 20th International Congress on Instrumentation in Aerospace Simulation Facilities - Gottingen, Germany
Duration: Aug 25 2003Aug 29 2003

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Flow measurement
velocity measurement
Flow velocity
Velocity measurement
plumes
flow velocity
Vacuum
Nitrogen
nitrogen
Electron beams
stagnation temperature
Angular velocity
electron beams
Test facilities
Gases
supersonic nozzles
vacuum
Ionization
expansion
Laser beams

All Science Journal Classification (ASJC) codes

  • Instrumentation
  • Aerospace Engineering
  • Condensed Matter Physics

Cite this

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title = "Flow velocity measurements in nitrogen plumes stimulated by REMPI",
abstract = "In the DLR-high vacuum plume test facility STG, experiments have been performed to study the expansion of supersonic plumes into vacuum with N 2 as a test gas. The measured values were the Pitot pressure, the molecular number flux, the rotational temperature and the density. The last two quantities were measured by the 2+2 REMPI-technique with a stimulation wavelength of 283-284 nm (REMPI = resonance enhanced multi photon ionization). This method is also suitable to measure the absolute flow velocity by the ion time-of-flight (TOF) method, The apparatus for the combination of the REMPI and TOF technique is similar to that for the TOF experiments using electron beam bombardment, but a focused laser beam is used instead of an electron beam. The results of such laser measurements in highly rarefied plumes for several stagnation temperatures are presented with nitrogen as test gas. On-axis results fit well with the theoretical limiting velocity for perfect expansion; angular velocity profiles off-axis are discussed and compared to theory. This study is focused on the experimental procedure to measure the flow velocity of N2 in rarefied plumes expanding from supersonic nozzles into vacuum.",
author = "Carl Dankert and Hideo Mori",
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AU - Dankert, Carl

AU - Mori, Hideo

PY - 2003/12/1

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N2 - In the DLR-high vacuum plume test facility STG, experiments have been performed to study the expansion of supersonic plumes into vacuum with N 2 as a test gas. The measured values were the Pitot pressure, the molecular number flux, the rotational temperature and the density. The last two quantities were measured by the 2+2 REMPI-technique with a stimulation wavelength of 283-284 nm (REMPI = resonance enhanced multi photon ionization). This method is also suitable to measure the absolute flow velocity by the ion time-of-flight (TOF) method, The apparatus for the combination of the REMPI and TOF technique is similar to that for the TOF experiments using electron beam bombardment, but a focused laser beam is used instead of an electron beam. The results of such laser measurements in highly rarefied plumes for several stagnation temperatures are presented with nitrogen as test gas. On-axis results fit well with the theoretical limiting velocity for perfect expansion; angular velocity profiles off-axis are discussed and compared to theory. This study is focused on the experimental procedure to measure the flow velocity of N2 in rarefied plumes expanding from supersonic nozzles into vacuum.

AB - In the DLR-high vacuum plume test facility STG, experiments have been performed to study the expansion of supersonic plumes into vacuum with N 2 as a test gas. The measured values were the Pitot pressure, the molecular number flux, the rotational temperature and the density. The last two quantities were measured by the 2+2 REMPI-technique with a stimulation wavelength of 283-284 nm (REMPI = resonance enhanced multi photon ionization). This method is also suitable to measure the absolute flow velocity by the ion time-of-flight (TOF) method, The apparatus for the combination of the REMPI and TOF technique is similar to that for the TOF experiments using electron beam bombardment, but a focused laser beam is used instead of an electron beam. The results of such laser measurements in highly rarefied plumes for several stagnation temperatures are presented with nitrogen as test gas. On-axis results fit well with the theoretical limiting velocity for perfect expansion; angular velocity profiles off-axis are discussed and compared to theory. This study is focused on the experimental procedure to measure the flow velocity of N2 in rarefied plumes expanding from supersonic nozzles into vacuum.

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