Efficiency and Pressure Loss Characteristics of an Ultra-Compact Combustor with Bulk Swirl

Research was conducted on a novel combustor design using a highly centrifugal loaded circumferential cavity to enhance flame speeds and lower mixing time to lower overall combustion time achieving improved efficiency and stability. This Ultra-Compact Combustor (UCC) is fed air with a bulk swirl, resembling gas leaving acompressor without the final set of compressor guide vanes to straighten the flow, athigher than normal Mach numbers for a combustor. The larger Mach numbers in the combustor do not cause a total pressure loss in excess of what Rayleigh theory woulddictate for the given heat addition taking place within the combustor. Tests were conducted on the UCC with a clockwise or counter-clockwise swirldirection in the circumferential cavity using JP-8 and natural gas derived Fischer-Tropschsynthetic jet fuel with each direction. The results for lean blow out stability, combustion efficiency, and emissions proved the best configuration uses counter-clockwise swirl. The two fuels performed equally with no noticeable differences between JP-8 and the synthetic Fischer-Tropsch fuel.