Accession Number : AD0718131

Title :   Rate Coefficients for Vibrational Energy Transfer in Rapid Expansions of Carbon Dioxide-Nitrogen Mixtures,

Corporate Author : STANFORD UNIV CALIF INST FOR PLASMA RESEARCH

Personal Author(s) : MacDonald,John R.

Report Date : DEC 1970

Pagination or Media Count : 200

Abstract : An investigation of vibrational energy transfer processes in a rapid expansion containing N2, CO2, and Ar is presented along with related analyses. In the experiment, arc-heated Ar was mixed with N2 and CO2 and a rapid expansion was obtained by expanding the gas mixture in an underexpanded free jet. The stagnation temperature was varied from 1900K to 2900K and the stagnation pressure was held near 2.7 atm. Particular emphasis was placed on ensuring gas purity and the test gas was analyzed to obtain quantitative measurements of gas purity. The vibrational temperatures of N2 and CO2 (V3) were determined from spatially-resolved spectroscopic measurements. In addition, information was obtained about the CO2(V3 + 3V2) intramolecular and the CO2 V-T processes in the rapid expansion. The results show that the rate coefficients needed to match the theory to the data generally exceed those measured in shock-heating and laser-fluorescence experiments. The importance of these measurements with regard to prediction of CO2-N2 gasdynamic laser performance is also discussed. (Author)

Descriptors :   (*CARBON DIOXIDE, RELAXATION TIME), (*GAS LASERS, ELECTRON TRANSITIONS), MIXTURES, NITROGEN, VIBRATION, MOLECULAR ENERGY LEVELS, SHOCK TUBES, TRANSITION TEMPERATURE, KINETIC THEORY

Subject Categories : Lasers and Masers
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE