ARAS MEASUREMENTS ON THE THERMAL-DECOMPOSITION OF CO2 BEHIND SHOCK-WAVES

The dissociation rate coefficient of CO2 has been measured behind reflected shock waves in the temperature range 2400≤T ≤4400 K at pressures 1.2≤p ≤2.0 bar. By the use of the atomic resonance absorption spectroscopy, the formation of O atoms could directly be observed in the postshock reaction zone. The experiments have been performed in mixtures of Co2 highly diluted in argon. The initial CO2 concentrations varied from 10 to 5000 ppm. The Arrhenius expression for the thermal decomposition of CO2, Co2 + M⟶kCO + O + M was found to be k1 = 3.65 × 1014exp(− 52,525 K/T) cm3mol−1 s−1. The effect of impurities was minimized by keeping background pressures in the shock tube below 5× 10−7 mbar. © 1990 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.