A comprehensive combustion chemistry study of n-propylcyclohexane

Alkylated cycloalkanes are vital components in gasoline, aviation, and diesel fuels; however, their combustion chemistry has been less investigated compared to other hydrocarbon classes. In this work, the combustion kinetics of n-propylcyclohexane (n-Pch) was studied across a range of experiments including pressurized flow reactor (PFR), jet stirred reactor (JSR), shock tube (ST), and rapid compression machine (RCM). These experiments cover a wide range of conditions spanning low to intermediate to high temperatures, low to high pressures at lean to rich equivalence ratios. Stable intermediate species were measured in PFR over a temperature range of 550–850 K, pressure of 8.0 bar, equivalence ratio (φ) of 0.27, and constant residence time of 120 ms. The JSR was utilized to measure the speciation during oxidation of n-Pch at φ of 0.5–2.0, at atmospheric pressure, and across temperature range of 550–800 K. Ignition delay times (IDTs) for n-Pch were measured in the RCM and ST at temperatures ranging from 650 to 1200 K, at pressures of 20 and 40 bar, at φ=0.5,1.0. In addition, a comprehensive detailed chemical kinetic model was developed and validated against the measured experimental data. The new kinetic model, coupled with the breadth of data from various experiments, provides an improved understanding of n-Pch combustion

Ignition delay time measurements of diesel and gasoline blends

Blends of diesel and gasoline can be used to achieve certain desired ignition characteristics in advanced compression ignition engine concepts. In this work, ignition delay times were measured for two blends of diesel and gasoline in two shock tubes and in a rapid compression machine. These blends comprised of 50/50 and 25/75 volumetric% of diesel and gasoline, respectively. To ensure complete vaporization of the blends, the prepared samples were analyzed with nuclear magnetic resonance (NMR) and laser ab- sorption. The analyses revealed full evaporation, and negligible decomposition/oxidation occurred during mixture preparation. Ignition delay measurements covered wide ranges of temperatures (710 1349 K), pressures (10 and 20 bar), and equivalence ratios (0.5, 1.0 and 2.0). The measured ignition delay times of the two dieseline blends are compared with experimental data of low- to mid-octane gasoline and low- to high-cetane fuels. The measured data are also compared with the simulated ignition delay times of primary reference fuel (PRF) and toluene primary reference fuels (TPRF) surrogates. Multi-component surrogates are proposed for the dieseline blends, and the measured ignition delays of the multi-component surrogates and the dieseline blends are in very good agreement.The paper is based on work supported by Saudi Aramco Research and Development Center FUELCOM program under Master Research Agreement Number 6600024505/01 and the Office of Sponsored Research (OSR) at King Abdullah University of Science and Technology (KAUST). FUELCOM (Fuel Combustion for Advanced Engines) is a collaborative research undertaking between Saudi Aramco and KAUST intended to address the fundamental aspects of hydrocarbon fuel combustion in engines, and develop fuel/engine design tools suitable for advanced combustion modes. The authors at NUI Galway recognize funding support from Science Foundation Ireland (SFI) via their Principal Investigator Program through project number 15/IA/3177.2022-09-2