Full gas dynamics and exergetic analysis of PGC cycles with rotating detonations

Gas turbine engines play an important role in transportation and power generation. Furthermore, the transportation and power generation industries are significant contributors of pollution and greenhouse gas emissions. Meanwhile, their usage grows annually, implying a significant increase in CO2 and NOx emissions. As the conventional gas turbine engines reach their efficiency limit, a promising solution to overcome this limitation is to redesign the gas turbine engine. One method is switching from constant pressure combustion to pressure gain combustion (PGC) which generates an increase in total pressure across the combustor and also proven to improve the thermal efficiency of the gas turbine cycle. This thesis is associated with one of the PGCs, the Rotating Detonation Combustor (RDC). In RDC, the detonation wave rotates in azimuthal direction around the combustor and the fuel-air mixture is injected axially. The detonation wave can be initiated either with Deflagration to Detonation Transition (DDT) tube or spark plug. The characteristics of RDC consists of injection, detonation wave, expansion wave, slip line and oblique shock. Although the RDC has the potential to improve gas turbine engines, there are complexities in the integration such as the exhaust flow of RDC is highly unsteady which complicates the RDC-Turbine integration and the flow temperature reaches up to 3000K, therefore to operate RDC for a longer duration, combustor cooling becomes essential. The present dissertation presents the analysis of the individual component and the overall cycle layout of the aircraft engine such as turbojet and turbofan. At the component level, the manuscript discusses about the modeling of RDC, RDC cooling, ejector, turbine mean line analysis, RDC-Turbine integration, turbine optimization and turbine film cooling. The overall cycle analysis is started with the steady state design point approach by varying the compressor pressure with fixed turbine inlet temperature. The performance metrics such as specific thrust, specific fuel consumption and thermal efficiency are evaluated along with exergy analysis. This steady state design point approach is extended for the part load cycle analysis which utilizes the characteristics maps of NASA Energy Efficient Engine's high pressure compressor and high pressure turbine. The thesis provides conclusive results that RDC with gas turbine engine provide better performance such as higher thrust, lower fuel consumption and higher exergy efficiency, when compared with the conventional gas turbine cycle.