Development and validation of a comprehensive combustion kinetic model for the oxidation of 3-hexene

Abstract

Alkene with a double bond present in the middle of the molecule is attractive as a representative of the olefinic group present in the long-chain unsaturated methyl esters, which make up biodiesel typically. Also the study of alkenes has long gained importance owing to its potential as a gasoline surrogate and its formation in significant amounts during alkane oxidation. These considerations motivate the study of kinetics of trans-3-hexene. In the current work, 3-hexene mechanism is developed upon the base chemistry of comprehensive NUIG1.3 mechanism. Several important reactions are revisited and are assigned rate constants from the literature, including theoretical studies. The revised kinetic mechanism has been validated at various temperatures, pressures, and equivalence ratios for different experimental configurations. The mechanism shows good agreement with ignition delay time data in the low to high temperature range. The mechanism also predicts the well known lack of negative temperature coefficient (NTC) behaviour in the case of alkenes with the central double bond. With the proposed kinetic model, it is possible to predict intermediate species profiles produced during 3-hexene oxidation satisfactorily. Path flux analysis and sensitivity analysis are performed in order to understand important reaction pathways and their effect on the combustion characteristics.