ORCh: A package to reduce and optimize chemical kinetics. Application to tetrafluoromethane oxidation

Abstract

ORCh is a set of C++ routines to analyze the response of detailed chemical kinetics and determine the most influential species and elementary reactions for given operating conditions. The objective is to reduce the number of degrees of freedom to be solved in fluid mechanics simulations while still capturing most of the reactive flow physics. From a detailed chemical kinetics, ORCh returns a set of reduced chemical schemes of decreasing complexity. ORCh operates either from canonical laminar diffusion–reaction problems, such as one-dimensional premixed and diffusion flames, or turbulent/chemistry interaction models through the evolution of stochastic particles. The initial conditions of these canonical problems are representative of the inlets of the reactive flow system under study. In case of a significant reduction of the number of degrees of freedom, the control parameters of the reduced chemistry can be further optimized from a genetic algorithm to still match the reference detailed chemistry response. An illustrative application to tetrafluoromethane oxidation chemistry is discussed.

Keywords

• Chemistry reduction
• Combustion
• Reactive flows
• Graph analysis
• Genetic algorithm