Theoretically Informed Kinetics (ThInK): Establishing a modern C0-C3 mechanism for combustion modeling

In contrast to the adage “Models are to be used, not believed”, combustion kinetics models have been intended to be predictive in nature. Theoretical chemical kinetics is now understood to provide a firm foundation for the reaction parameters, thereby facilitating predictive simulations of chemical reactivity, even in regimes that are poorly characterized by chemical kinetic and/or combustion experiments. We describe here a theory-informed kinetics model (ThInK) for small molecule combustion chemistry (H₂ and C₁ – C₃ species) that is based on the prodigious use of theoretical predictions for reaction rate coefficients, thermochemistry, and transport parameters. The distinct features of this kinetics model, which was developed over the course of several decades, are illustrated through simulations of flame propagation and auto-ignition.

Novelty and significance statement

The novelty of the “ThInK” C₀–C₃ mechanism is that an overwhelming number of its parameters are derived from a priori theoretical predictions. It marks a significant departure from traditional models that rely heavily on experimental data and adjusted or empirical parameters. This advancement represents a transformative step in the modeling of combustion kinetics, providing an exceptionally robust small-molecule core mechanism upon which larger models can be based.