Review of Applications of Rate-Controlled Constrained-Equilibrium in Combustion Modeling

Abstract

AbstractDeveloping an effective model for non-equilibrium states is of great importance for a variety of problems related to chemical synthesis and combustion. Rate-Controlled Constrained-Equilibrium (RCCE), a model order reduction method that originated from the second law of thermodynamics, assumes that the non-equilibrium states of a system can be described by a sequence of constrained-equilibrium states kinetically controlled by a relatively small number of constraints within acceptable accuracy. The full chemical composition at each constrained-equilibrium state is obtained by maximizing (or minimizing) the appropriate thermodynamic quantities, e. g., entropy (or Gibbs functions), subject to the instantaneous values of RCCE constraints. Regardless of the nature of the kinetic constraints, RCCE always guarantees a correct final equilibrium state. This paper reviews the fundamentals of the RCCE method, its constraints, constraint potential formulations, and major constraint selection techniques, as well as the application of the RCCE method to combustion of different fuels using a variety of combustion models. The RCCE method has been proven to be accurate and to reduce computational time in these simulations.