Confined Recirculation Combustion Afterburner

The future of manned and unmanned vehicles requires significant improvements in engine thrust-to-weight ratio, efficiency, length, and cost. These improvements may be realized in the afterburner for supersonic missiles, Mach 8-10 strike/reconnaissance aircraft, and hypersonic vehicles operating with a Turbine Based Combined Cycle (TBCC). Spiritech Advanced Products, Inc. proposes to increase the thrust -to-weight ratio of turbine engines by decreasing the length of the afterburner. This is to be accomplished through Confined Recirculation Combustion (CRC). In a well-designed afterburner, combustion efficiency is determined by the fuel residence time. For conventional afterburners, high efficiency comes at the expense of a long duct. In the CRC afterburner, some or all of the fuel, is injected into a cavity that recirculates a portion of the airflow, increasing the residence time of the fuel without increasing the length. In addition, the recirculating zone can act as a pilot at high power conditions when additional fuel is injected into the main flow. The Phase I effort will focus on verifying the feasibility of this concept and will provide; a parametric design matrix, calibration of design matrix in AFRL's High-Pressure Combustor Research Facility, conceptual design methodology/guidelines, CFD analysis, and conceptual design for Phase II demonstration test.