An advanced multi-configuration stator well cooling test facility

The optimisation of cooling systems within gas turbine engines is of great interest to engine manufacturers seeking gains in performance, efficiency and component life. The effectiveness of coolant delivery is governed by the complex flows within the stator wells as well as the interaction of main annulus and cooling air in the vicinity of the rim seals. This paper reports the development of a test facility which allows the interaction of cooling air and main gas paths to be measured at conditions representative of those found in modern gas turbine engines and presents data obtained over the range 2x10 6 < Reφ < 2.3x106. The test rig comprises a two stage turbine section with an overall pressure ratio of approximately 2.7:1 at the design condition. Hot air is supplied to the main annulus using an adapted Rolls-Royce Dart compressor driven by a 5 MW aero derivative engine plant. Cooling air is delivered to the stator wells at multiple locations and with a range of flow rates, covering ingestion and egress. The rig has been designed with adaptable geometry to facilitate rapid changes of cooling air path configuration. The coolant delivery system allows swift and accurate changes to the flow settings whilst the rig is running such that thermal transients may be performed. Particular attention has been focused on obtaining high accuracy data, using a radio telemetry system, as well as thorough through-calibration practices. This has allowed temperature measurements to be made on both rotating and stationary discs with an uncertainty in the region of 0.3 K. A novel gas concentration system has also been developed, in order to obtain measurement of re-ingestion and rim seal exchange flows, while high resolution displacement sensors have been installed in order to measure hot running geometry. This paper demonstrates the commissioning of a unique test facility with flexible functionality. Example data from the commissioning phase which the effect of increased cooling flow on stator well metal temperatures. The engine representative test conditions together with the unique density and accuracy of the measured data will support validation of the next generation of conjugate/coupled models to be used for the optimisation of internal cooling systems.