Reduction of comprehensive chemistry via constraint potentials

According to the concept of rate-controlled constrained equilibrium (RCCE), combustion kinetics can be reduced into a set of constraints whose relaxation guides the evolution of the system towards equilibrium. In this work, a formulation of RCCE in terms of thermodynamically derived variables (constraint potentials) for a constant pressure-enthalpy system is presented and employed in conjunction with a comprehensive mechanism for CH4 combustion comprising 63 species and 415 reactions, including N chemistry. The outcome is tested by means of homogeneous combustion and pairwise-mixed stirred reactor (PaMSR) calculations, and it is shown that sets of few variables are able to provide very accurate prediction of the major species, and moderately successful prediction of NO. © 2004 The Combustion Institute.