LT-HyChem - A physics-based chemical kinetic modeling approach for low-temperature oxidation of real fuels I: Rationale, methodology, and application to a simple fuel mixture

The diversity of reactivities, intermediates, and pathways associated with the low-temperature (low-T) oxidation of various component classes that constitute real fuels is perhaps the most challenging aspect of modeling their combustion chemistry. Unlike high-temperature oxidation (T > 1100 K), where the combustion properties of multicomponent fuels are relatively insensitive to compositional variations, reactions governing low-T oxidation exhibit pronounced sensitivity to fuel composition. Despite the fuel specificity, intermediate formation during low-T oxidation exhibits characteristic behaviors. Combining such observations and the already mature Hybrid Chemistry (HyChem) methodology for high-temperature oxidation of real fuels [1], we propose a framework to develop simplified, physics-based chemical kinetic models for low-T oxidation of real fuels. The proposed model captures the complexity of low-T oxidation through concise, fuel-specific reactions whose stoichiometric parameters and rate constants are experimentally constrained. Shock tube experiments needed for constraining model parameters are identified and plausible validation targets are discussed. The present paper outlines the model's description, its underlying physical principles, and an initial application to a simple, multi-component mixture, TPRF-60. Detailed uncertainty analyses and application to three real fuels will be presented in a companion paper.