Product Distribution and Induction Times in the Shock-Initiated Ignition of Cyanogen-Oxygen-Argon Mixtures

Mixtures of cyanogen and oxygen diluted in argon were ignited behind reflected shocks in a single-pulse shock tube. The ignition delay times were determined from pressure observations. The experiments covered the temperature range 1400 K to 2000 K. This range permitted ignition delay times from 15 to 430 microseconds. Eight mixture groups and their initial conditions were chosen in such a manner that the influence of each particular parameter on the induction period would be unequivocally evaluated. The resulting equation for induction time was determined. Product distribution before and after ignition was determined by mass spectroscopy. Results indicated that the combustion of cyanogen is thermodynamically controlled. Hydrogen lowers activation energy and shortens induction time. This indicates that with the addition of H2 a chain branching mechanism becomes rate controlling. Modified author abstract)