Use of an Ultra-Compact Combustor as an Inter-Turbine Burner for Improved Engine Performance.

摘要

An Inter-Turbine Burner (ITB) represents a novel mechanism for generating additional work from a gas turbine engine in applications where an afterburner would typically be used. An ITB can achieve higher thermal effciencies over a typical afterburner while also generating shaft work versus only additional thrust. In an effort to investigate the potential applications for the ITB, a numerical engine cycle comparison was made between the ITB cycle and a conventional afterburning cycle using the Numerical Propulsion System Simulation (NPSS). In the case of thrust augmentation, the ITB model outperformed the afterburning model when Thrust Specific Fuel Consumption (TSFC) is compared to increased thrust, but resulted in decreased fan effciency and High Pressure Compressor (HPC) stall caused by fan overspeed. In the case of Power Extraction (PX) augmentation the ITB engine achieves similar TSFC results without experiencing component effciency loss or approaching HPC stall. For the PX augmentation model, the pressure drop across the ITB was varied from 4% to 20%. Large pressure drops were found to increase the TSFC and reduce the HPC stall margin for the ITB model. ITBs are expected to achieve pressure drops between 3% and 5% and for this range the ITB will continue to be more fuel e cient than the afterburning engine model. An experimental investigation was performed focused on integrating the AFIT ITB to accept a common flow source. Three common flow source diffusers with core to bypass inlet area percentage ratios of 80/20, 70/30, and 60/40 were tested. All three diffuser designs were found to su er from flow reversal in the bypass stream caused by instances of greater total pressure in the core flow than in the bypass flow. The baseline thrust performance for the JetCat P200 Small Turbine Engine (STE), which will serve as the AFIT ITB vitiated air source, was determined and found to be consistent with manufacturer specifications.