Development of a Cryogenically Pumped Mass Spectrometer Probe for Rocket Plume Studies
Final rept. 1 Jul 1972-30 Jun 1975
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN
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Two cryogenically cooled 20K mass spectrometer probes were developed for sampling species concentrations in a rocket exhaust plume. A flat- face probe with a cryogenic 20K skimmer and a conical probe with a warm 20-deg half-angle conical skimmer were evaluated in room temperature free-jet expansions of nitrogen, argon, and gas mixtures containing hydrogen. Cryosorption pumping of hydrogen by 20K CO2 frosts was employed within the probes. Typical probe pressures were maintained on the 10 to the 7th power torr scale. Species densities were measured in the room temperature free jets and calibrations determined. The flat-face probe was determined to be unsuitable for rocket testing. The conical probe was tested in the exhaust plume of a 1-lb thrust MMHN2O4 liquid rocket engine and major species concentrations were determined for several OF ratios. Qualitative minor specie measurements were also made.
- Test Facilities, Equipment and Methods