An Aromatics and cC_5H_(5-8) Model with Improved Transport for Flat Flames, Flow Reactors and Shock Tubes

摘要

Presenting improvements to a detailed, quantitative, 1-dimensional, kinetic, aromatics and cC_5H_(5-8) submodel with thermodynamics and transport. The model, with ～250 species and ～2000 reactions, includes a full NO_x chemistry sub-model. Transport parameters: ε, σ and α are all determined by empirical or experimental data. Most μ values are given by experimental values for the parent compounds and empirically for their radicals. Z_(rot) has been set to 1 or experimental values. Shock tube conditions are explored. Flow reactor and flat flame results are updated. Selected experiments on toluene, benzene, cyclopentene (CPE) and cyclopentadiene are examined. A new method is implemented to avoid arbitrarily time-shifting the modeling data to match the fuel concentration at 50% consumption. Instead, the method of least squares fits the experimental data to a 1st-3rd order polynomial. The least squares value is compared against the modeling calculations and a root-mean squared (RMS) goodness of fit (GoF) is calculated. The time shift is then determined numerically to the millisecond by minimizing the GoF. Similarly when tuning the model using the concentrations of 1,3-cyclopentadiene (CPD) Indene, Benzene or sums of C_4 and C_3 species a GoF is used to iteratively determine the best rate constants. With this latest version of the model it is no longer necessary to tune rate constants for naphthalene, 1,2-dihydronaphthalene or 1-phenyl-1,3-butadiene. The model is compared to the experimental oxidation of CPD in an atmospheric pressure flow reactor and a shock tube. Side products for two reactions have been changed from 2H to H_2 to avoid early and unrealistic chain branching: 2 cC_5H_6 → 1,2 dihydronaphthalene + H_2 and 2 cC_5H_6 → 1-phenyl-1,3-butadiene + H_2. The main naphthalene formation route is now 2 cC_5H_5 → C_(10)H_8 + H_2 with k=10~(11)×e~(-34000/(8.314×T)) cm~3 mol~(-1)s~1. Other changes in derived rates are discussed.