Wave Attenuation and Interactions in a Pulsed Detonation Combustor-Turbine Hybrid System

A large-scale, multi-tube pulsed detonation combustor with eight tubes arranged in a can-annular configuration was integrated with a single-stage axial turbine nominally rated for 8 lbm/s, 25000 RPM and 1000 hp. This PDC-turbine system was operated using ethyleneair mixtures with each tube firing at 20 Hz. High frequency pressure transducers were installed throughout the flow path to investigate the wave interactions and attenuation across the turbine. The multi-tube PDC was operated at a range of conditions with three firing patterns: a single tube firing, all tubes simultaneous and all tubes sequential. Analysis of these data reveal wave interactions in the transition plenum between the PDC exit and turbine inlet plane can affect the optimum operation of the multi-tube PDC. In addition, there is over 20 dB attenuation of the peak pressure pulse and 10 dB attenuation of the broadband acoustic noise through the single-stage, axial flow turbine.