Establishment of a set of skeletal oxidation mechanisms for mono-alkylated cyclohexanes with consistent structure

Abstract

As a major chemical class of fossil fuels, mono-alkylated cyclohexanes are frequently employed to construct the surrogate fuels of fossil fuels. Much effort has been made to study the oxidation behavior of mono-alkylated cyclohexanes, but reduced/skeletal mechanisms suitable for multi-dimensional combustion simulations are still scarce. In this work, a set of skeletal models for mono-alkylated cyclohexanes from methyl-cyclohexane (MCH) to octyl-cyclohexane (n-OTCH) were built and deduced by integrating the decoupling methodology and reaction rate rules. The development process contains two parts, i.e., the skeletal model establishment for the base fuel and the skeletal model deduction for other fuels utilizing the reaction rate rules. For mono-alkylated cyclohexanes, the reactions in the fuel-relevant sub-model also dominate the laminar flame speed, apart from the C0–C3 sub-model, which differs from that of n-alkanes. To well capture the flame propagation behavior, the local sensitivity analysis on the comprehensive mechanism was introduced. For each mono-alkylated cyclohexane, the skeletal model includes 52 species and 216 reactions. The final skeletal models were validated against extensive experimental measurements in jet-stirred reactors, shock tubes, rapid compression machines, and premixed flames over wide operating conditions. Satisfactory agreements between the observed data and simulated results are achieved, which indicates the practicability of the proposed method.