The combustion of fuel reference compounds in laboratory-scale reactors and flames

Banyon, Colin
Internal combustion engines that rely heavily on fuel oxidation chemical kinetics, rather than external ignition sources, promise the simultaneous improvement of thermodynamic efficiencies and reduction of pollutant emissions compared to more conventional designs. Unfortunately, the successful operation of these engines require predictive chemical kinetic models to assign ignition parameters to engine maps. This work adds to the growing database of chemical kinetics experiments for sixteen (potential) transportation fuel surrogate compounds that all constitute large fractions of gasoline. In detail, shock tube and rapid compression machine experimental campaigns have been conducted for the five isomers of hexane, the nine isomers of heptane, cyclopentane and toluene, where ignition delay times over a wide range of conditions have been measured. A considerable amount of effort has been put forth to extend the capabilities of these experimental platforms to handle relatively large, gasoline relevant fuels. Through large collaborative efforts, detailed chemical kinetic models for the oxidation of these fuels have been constructed/updated in light of this new data. Although, these fundamental models are robust, with the capability to predict a large number of chemical parameters important to engine operation, they are also computationally expensive. A computationally lean, alternative approach for the storage of ignition delay time data has also been developed in this work, where non-Arrhenius ignition delay times can be accurately stored in terms of eight parameters. This thesis also investigates the role of in-cylinder chemistry in more conventional spark, compression ignition and gas turbine engines. New ignition delay time data are presented for the cetane enhancer 2-ethyl-hexyl nitrate. Also, the role of endothermic chemistry in diesel sprays has been computationally evaluated. Further, the coupling between flow motion and the formation of stable combustion intermediates in swirl stabilized flames has been investigated, based on the recent trend of gas turbine and large-bore marine engines to use swirl as a lean charge combustion stabilizer.
NUI Galway
Publisher DOI
Attribution-NonCommercial-NoDerivs 3.0 Ireland