Ten Years of Turbine Research at NG-Turb: Recent Upgrades, and Upcoming Extended Reynolds Number Range

Kurzfassung

The Next Generation Turbine Test Facility (NG-Turb) at the German Aerospace Center (DLR) has been developed to investigate aerodynamic and aerothermal phenomena in axial turbines under engine-representative conditions, with a particular focus on high-pressure turbine (HPT) applications. The facility enables independent control of Mach and Reynolds numbers in a continuously operating, closed-loop environment, allowing multi-stage turbine investigations under stable boundary conditions with high measurement accuracy. Since its commissioning in 2015, NG-Turb has undergone significant upgrades to improve operational stability, measurement capability, and experimental flexibility. Key developments include a revised temperature conditioning concept, an expanded secondary air system for engine-relevant cooling investigations, and the replacement of the Venturi nozzle with an ultrasonic flow meter, reducing uncertainty over a wide operating range. In addition, the integration of a second drive line enables dual-shaft, counter-rotating turbine operation. A further upgrade, currently under development, will extend the accessible Reynolds number range by increasing turbine inlet pressure. This will allow systematic investigations at significantly higher Reynolds numbers while maintaining representative flow conditions. The paper summarizes the facility evolution and demonstrates the impact of the upgrades on performance, stability, and measurement quality. The resulting infrastructure provides a robust experimental basis for the validation of advanced CFD methods and the development of next-generation turbine designs