PREMIXED, TURBULENT COMBUSTION OF AXISYMMETRICAL SUDDEN EXPANSION FLOWS

Velocity and low-frequency combustor pressure oscillations have been measured in a ramjet dump combustor model. The mean and root mean square (rms) values of the turbulent velocity field were obtained using a two-component laser Doppler velocimeter (LDV) system operating in the backscatter mode. Reacting flow data were obtained for premixed propane and air, while isothermal results were collected after replacing the propane with nitrogen. The velocity data indicated substantial differences between the two cases Combustor pressure oscillation data were also obtained. The intensity and frequency of the oscillations were found to be dependent on the inlet velocity, combustor length, and equivalence ratio. Results showed that pressure oscillations were controlled by both vortex kinematics in the combustor and acoustic response of the inlet section.