Design Procedure of a Rotating Cavity Rig for Hot Gas Ingestion Investigation

This paper presents the design procedure and the setup of a Rotating Cavity Rig to investigate the problem of the high-pressure turbine main annulus flow ingestion into wheel-spaces. The single-stage test rig has been developed to run at cold flow conditions and it consists of a stationary and a rotating disk housing interchangeable cover plates to mimic different seal geometries. Thanks to such interchangeable covers, the rim seal configuration can be easily modified to investigate different arrangements and to perform optimization studies. Although some geometry simplifications are inevitable in scaled down models, such covers have been modelled as to represent a real engine rim seal as close as possible. Beside the standard pressure and CO2 concentration measurements inside the cavity, the rig implements optical accesses to exploit measurement techniques based on Pressure Sensitive Paints (PSP). Optical approaches will then be used to explore the rim sealing effectiveness on both stator and rotor disk under real engine representative operating conditions. CFD and FEM analyses run to support the rig design choices and to define its operating limits are hence highlighted and properly explained.