Experimental studies of simple hydrocarbons in a shock tube

Abstract

Chemical kinetic models are needed to simulate fuel chemistry in combustion devices and to aid in the development of new designs to reduce harmful emissions and maximize combustor performance. However, these models need to be validated using fundamental experimental data to ensure that they are accurate in their predictions. The three main objectives of this doctoral project are: 1. Recommission an existing shock tube to perform ignition delay time (IDT) experiments. 2. Convert the shock tube to ‘single-pulse’ mode and implement sampling techniques to analyze the post-shock heated analyte using a gas chromatography - mass spectrometry system. Characterize and validate the new reactor. 3. Generate a species mole fraction database from numerous hydrocarbon pyrolysis experiments. In the current project, the NUI Galway (NUIG) low pressure shock tube (LPST) is recommissioned and initially, validated against n-heptane data. This facility is used for studying the oxidation of C1 – C3 alkanes, alkenes and their mixtures. In the second phase of the project, the shock tube is converted to single-pulse shock tube (SPST) and validated using cyclohexene, isobutene and 1,3-butadiene. Post-validation, we studied C2–C6 1-alkenes, pentene isomers, allene, propyne, 2-butene, tetramethyl ethylene and isoprene. A new mechanism NUIGMech1.0 is formulated and used to simulate the data and the predictions for the major species are satisfactory. The improvement in predictions of the current mechanism, which includes C6 and C7 species, is substantial compared to AramcoMech3.0. Overall, all the three objectives of the project were met within the allotted time and budget.