Dynamics of Expanding Flames

An experimental apparatus and methodology are developed to determine the laminar flame speeds of high molecular weight fuels. In order to achieve this goal, an asymptotic analysis of the propagation of premixed flames in a confining vessel is first performed. As a result of this analysis, a relationship between the stretched flame speed and the stretch rate is derived. This mathematical relationship is later applied as a means to extrapolate experimental measurements to determine the unstretched laminar flame speed and results in a substantial improvement over previous methods of extrapolation. Following the asymptotic analysis of the flame, two experimental studies are reported. The first experimental study determines the criteria for successful spark ignition of a combustible mixture and gives a physical interpretation of the criterion. The second study experimentally determines the laminar flame speeds and Markstein lengths for various hydrocarbon fuels and fuel mixtures. The fuels studied are either representative components of alternative fuels or are single component alternative fuels. As such, these measurements are critically important to the validation and understanding of the combustion of alternative fuels. The resulting measurements are compared with chemical kinetic mechanism predictions to determine areas for improvement in the chemical kinetic modeling of alternative fuels