Recent advances in additive manufacturing and advanced measurement capabilities are enabling the acquisition of high-fidelity turbine cooling data at increasingly relevant conditions with rapid turnaround. Of particular interest is exploring manufacturing variation on true-scale parts, as well as advanced cooling features for conventional and novel turbine materials, at representative Mach and Reynolds numbers. This study presents the design and benchmarking measurements for a new steady transonic linear cascade at Penn State. The facility can hold up to 11 turbine blades at true scale, with high span to chord ratio for two-dimensional flow at the airfoil midspan. The cascade is constructed of stainless steel for high wall stiffness but has provisions for significant instrumentation access. Mainstream air at 120°C and 4.5 bar is provided from a 1 MW compressor, while desiccant dried air at -100°C can be used as the cooling flow to match coolant-to-mainstream density ratios. The current cooling system can supply three airfoils, each with three independent cooling circuits, to enable parametric studies of cooling with good periodicity for central airfoils. Independent Mach and Reynolds number control at steady conditions is achieved through the use of upstream and downstream control valves, as well as a cascade bypass loop. Tests at various incidence angles can be performed through the use of a turntable and modular guide wall system. Optical windows include a zinc selenide window for spatially resolved surface temperature measurements using infrared thermography, as well as glass windows for flowfield measurements using laser-based flow diagnostics. The infrared camera and window setup enables a 360 degree view around the surface of the central airfoil, as well as a direct orthogonal view of the tip and endwall surfaces. For laser-based flow diagnostics, the window can be replaced with glass and laser sheets can be delivered to the central airfoil through glass inserts in the guidewalls. Benchmarking results for the facility include blade surface static pressures, inlet and exit endwall static pressures, inlet boundary layer thickness, and freestream turbulence measurements at various Mach numbers, Reynolds numbers, and incidence angles. Results are compared against CFD and other experiments performed on the same airfoil geometry for validation of the facility. The procedure to ensure accurate calibration of infrared thermography measurements of cooled airfoils is described, and preliminary results are shown. Future studies in the facility will investigate film cooling behavior at transonic conditions, the effect of manufacturing accuracy on film cooling, and the use of 3D printing to generate cooled airfoils using novel materials.


A Steady Transonic Linear Cascade for True Scale Cooling Measurements

Division / Sponsor:
International Gas Turbine Institute (IGTI)

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2020/volume/84058

Turbo Expo - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.