Experimental Investigation of the Energy Distribution Among Turbulence Through Proper Orthogonal Decomposition Inside an Annular Turbine Exit Guide Vane Cascade With Purge Cavity Air

Abstract The thermal efficiency of jet engines increases with enhanced combustion exit temperatures. Consequently, the fluid’s total temperature downstream of the Low-Pressure Turbine (LPT) increases, too. Thus, a method is needed to prevent hot gas from entering the slot cavity between LPT’s last rotor row and the stationary Turbine Rear Frame (TRF). As a result, cold air gets extracted from the Low-Pressure Compressor and purged into the rim seal cavity, which eventually enters the main gas path at the hub upstream of the TRF’s Turbine Exit Guide Vanes (TEGV). Experimental data is recorded inside a high-speed wind tunnel downstream of a Turbine Exit Guide Vane cascade. The study presents findings on the energy distribution among turbulent characteristics of the flow field downstream of an annular Turbine Exit Guide Vane Cascade. Moreover, the impact of cavity air purged into the main gas path through a rim cavity upstream of the stationary cascade is considered. Fundamental cycle considerations yield a correction method to distinguish between various viscous work inputs. Constant Temperature Anemometry (CTA) is used for transient data acquisition, and Proper Orthogonal Decomposition (POD) is utilized to identify the primary contributors in terms of energy. Two operating conditions are investigated, representing the aircraft states.