Announcing the Final Examination of Robert Rodgers for the degree of Doctor of Philosophy
Experimental data of flame blowout is used to develop a modified flame stability correlation parameter (SCP) for supersonic non-premixed flames. The problem was approached by identifying the key physical parameters which affect the SCP. There are two categories with which the physical parameters are separated, the flow timescale and the chemical timescale, the ratio of which is the inverse Damkohler number. The flow timescale parameters were able to be isolated using upstream fueling data. This data most closely resembled premixed fueling at the supersonic flow conditions. The flow timescale was found to be affected by the Mach number, temperature, and the pressure for both upstream and direct cavity fueling. Mach is a function of temperature; thus, a correlation was able to be determined with a Mach number, isentropic flow ratio, and a temperature ratio. The pressure ratio term identifies a pressure rise due to supersonic flow across the jet-induced and flame-induced shocks waves. An empirical relationship was then found by scaling the Mach number, pressure, and temperature. It was found that the flow timescale increases proportionally with Mach and temperature and inversely with pressure. The chemical timescale was studied using both upstream and direct cavity fuel injection. The data was analyzed after applying the SCP modifications found from the flow timescale analysis. The chemical timescale was shown to be affected by pressure, temperature, fuel type, and geometry. An empirical relationship was found for chemical timescale. The parameter identifies that the chemical time scale increased with the same trends as the flow timescale. The data was found experimentally with a supersonic cavity flameholder combustor. CD nozzles were used to produce Mach 1.8-3 inlets. The cavities were both rectangular and axisymmetric in geometry. Fuel injection was used in both upstream and direct cavity configurations
Committee in Charge:
Kareem Ahmed, Chair, MAE
Michael Kinzel, UCF Faculty
Jayanta Kapat, Mechanical & Aerospace Engineering
Timothy Ombrello, Air Force Research Labatory