Autoignition of Methyl Valerate at Low to Intermediate Temperatures and Elevated Pressures in a Rapid Compression Machine

<div>Presented at the 10th US National Technical Meeting of the Combustion Institute in College Park, MD on 25 April 2017</div><div><br></div><div>Methyl valerate (C<sub>6</sub>H<sub>12</sub>O<sub>2</sub>, methyl pentanoate) is a methyl ester and a relevant surrogate component</div><div>for biodiesel. In this work, we present ignition delays of methyl valerate measured using a rapid</div><div>compression machine at a range of engine-relevant temperature, pressure, and equivalence ratio</div><div>conditions. The conditions we have studied include equivalence ratios from 0.25 to 2.0, temperatures</div><div>between 600-1100 K, and pressures of 15 and 30 bar. The ignition delay data demonstrate a negative</div><div>temperature coefficient region and two-stage ignition response in the temperature range of 700-800 K</div><div>for the equivalence ratios of 1.0 and 2.0 and pressure of 30 bar. In addition, the experimental</div><div>ignition delay data are compared with simulations using an existing chemical kinetic model from the</div><div>literature. The simulations with the literature model underpredict the data by factors between 2 and</div><div>10 over the entire range of the experimental data. To help determine possible reasons for the</div><div>discrepancy between simulations and experiments, a new chemical kinetic model is developed using the</div><div>Reaction Mechanism Generator (RMG) software. The agreement between the experimental data and the RMG</div><div>model is improved but still not satisfactory. Directions for future improvement of the methyl</div><div>valerate models are discussed.</div><div><br></div>