Radial Rotating Detonation Engine Driven Bleed Air Turbine

Abstract

There has been a recent need for rapid response power generation device on aircraft. Current power generators consume a large portion of the aircraft’s usable volume, and they are also extremely heavy relative to their power output; therefore, the need for compact, power-dense auxiliary power units or bleed air turbine (BAT) arose. A solution comes in the form of coupling rotating detonation engines (RDEs) with a turbine generator. Previous work on RDE turbine integration has been successfully demonstrated with significant power extraction, but a modification leading to a more compact form with higher power density would be beneficial. Therefore, a new type of RDE referred to as the radial rotating detonation engine (RRDE) was developed for use as a combustor for a BAT. This design was based on a disk-shaped device within which reactants flow from the outer radius, detonate, and then exit the inner radius. Here the flow was routed into a compact centrifugal turbocharger turbine to extract the power. The power extracted from the turbine was measured using the compressor side of the turbocharger as a brake. Three different nozzle guide vanes changed the flow angle into the turbine. Various mechanisms of backpressuring the device were also accomplished over a range of mass flows. The results show significant power output from the device of over 60 kW at an operational speed over 110 kRPM. The RRDE configuration suffers from losses in the system, but has the potential for overall thermal efficiencies of up to 40%. The results also suggested that the interactions between the combustion chamber and the nozzle guide vanes may be a large source of losses. Finally, the addition of compressor backpressure and turbine backpressure plates did not affect the operating mode of the RRDE, but did improve the output power of the system.