Chemical Kinetics of the Shock-Initiated Combustion of Hydrogen at High Pressure and Low Temperatures

Abstract

The ignition mechanism of the hydrogen–oxygen explosion at temperatures near 1000°K and pressures greater than 1 atm was investigated theoretically using the complete analytic solution to the kinetic equations of an abbreviated, linearized mechanism and numerical integration of the full conventional mechanism for these conditions. It was found that the analytic solution of the simplified mechanism is capable of only a qualitative description of the second limit effect observed in reflected shock experiments on ignition delays, and cannot be forced to yield quantitative agreement. The numerical integration can be forced to give quantitative agreement, but only at the cost of accepting rate-constant expressions which do not allow quantitative description of the simpler ignition phenomena at higher temperatures and lower pressures. An exception to these conclusions is the use of analytic expressions for interpretation of branching rates early in the induction zone, which appears to be valid within wide limits.