MEASUREMENT OF ELECTRON TEMPERATURE AND NUMBER DENSITY IN SHOCK-TUNNEL FLOWS .2. NO+ + E- DISSOCIATIVE RECOMBINATION RATE IN AIR

The dissociative-recombination rate coefficient for the reaction NO+ + e− →k N + O has been measured in the inviscid nozzle flow of a short-duration reflected shock tunnel and found to be given by kr = (6.7 ± 2.3) × 1021 Te-1.5 cm3/mole sec for an electron temperature range of approximately 2000-7000 °K. These experiments were performed in air at equilibrium reservoir conditions of 6850°K and 22 atm pressure and at 7200°K and 25 atm pressure. Thin wire Langmuir probes were used to measure the electron temperature and electron density on the nozzle centerline. The electron densities were simultaneously measured using microwave interferometers and found to be in good agreement with the values obtained from the Langmuir probe data. The measured electron temperatures, which were considerably greater than the calculated heavy particle translational temperature, were used in determining kr from the number density data. © 1969 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.