A reduced kinetic model for the oxidation of supercritical ethanol/gasoline surrogate blends

In recent decades, significant global attention has been devoted to mitigating the negative consequences of air pollution and vehicular emissions on public health and climate change. One technology that has shown promise in reducing particulate engine emissions is supercritical combustion. This study introduces a reduced kinetic model (155 species and 1106 reactions) for oxidation analysis of supercritical ethanol/gasoline blends. A combination of reducing techniques (sensitivity Analysis and the directed relation graph error propagation) and a combination process (reaction packages method) were used to develop a new reduced ethanol/gasoline surrogate mechanism. The validity of the reduced combined mechanism was assessed using 0D constant-volume auto-ignition delay times (IDT) and 1D laminar flame speed simulations against experimental results. A modified cubic Redlich–Kwong equation of state was used to classify the state of each literature mixture tested in this work as supercritical or sub-critical, which can cooperate and endorse the supercritical combustion processes into engines. The proposed gasoline/ethanol mechanism provides consistent IDT results concerning the experimental shock tube data under high pressure for gasoline surrogate/ethanol/air blends at 30–55 atm and for pure ethanol/air at 20, 30, and 75 atm. The gasoline surrogate IDT results agreed well at the temperature range of 720 K up to 1250 K. Although the ethanol IDT results had an excellent agreement for the high-pressure (75 atm) and intermediate and high-temperature conditions (≥\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\ge$$\end{document} 850 K), it has a slightly lower agreement at 20 and 30 atm and temperatures lower than 800 K.