Aerodynamics of Turbine Rim-Seal Ingestion

This paper describes the theoretical modelling of the flow in a rotor-stator wheelspace with ingestion through the rim-seal. The predictions are compared with experimental measurements of pressure taken for an axial clearance rim-seal downstream of a set of nozzle guide vanes. The mainstream pressure asymmetry caused by the guide vanes was measured in the absence of coolant flow. Using this data, three-dimensional CFD calculations were carried out, providing both predictions of the cavity pressures and insight into the flow mechanisms involved. The CFD predictions gave good agreement with experiment at low coolant flow rates. However, at high coolant flow rates, disagreement with the experimental results is evident, suggesting that the interaction between the coolant flow and the mainstream flow through the nozzle guide vanes could no longer be ignored.