Deflagration regimes of laminar flames modeled after the ozone decomposition flame

Abstract

Methods of activation-energy asymptotics are employed to investigate regimes of combustion of steady, planar, adiabatic deflagrations involving a four-step kinetic mechanism modeled after that of the ozone decomposition flame. The analysis demonstrates the occurrence of previously known regimes having flame structures that involve a nonreactive preheat zone followed by a narrow reactive-diffusive zone, in which a steady-state approximation for the reaction intermediary may or may not apply and downstream from which a recombination zone may or may not exist. In addition, a new regime is identified having a two-zone flame structure in which the intermediary is generated in a downstream zone that obeys a steady-state approximation for temperature and diffuses into an upstream zone where the primary heat release occurs. In this regime convection, diffusion, and reaction all are important in both zones, and heat release persists in the preheat zone all the way to the cold boundary. For the ozone flame new results for burning velocities are given and regimes are identified as functions of pressure, initial temperature, and initial ozone concentration.