An Investigation of Lock Plate Flow

Lock plates are used on some turbine disc assemblies to secure the location of the blades. The pressure ratio across blade roots and the associated clearances inevitably means that there is some leakage through the abutting mating surfaces of the lock plates. This flow is ejected into the corresponding stator well or rotor-stator disc wheelspace. The aim of this study was to investigate the level of penetration of this flow and therefore its potential impact on and interaction with the wheelspace flow and associated heat transfer. Given the low mass flow associated with this leakage, typically less than one percent of the mainstream annulus flow, generation of the validation data was undertaken using a representative wind tunnel slot array. This paper reports the experimental data and corresponding CFD flow predictions and discusses the resultant insight obtained. For the experiments and associated modeling undertaken it was found that the injected flow did not penetrate the cross flow boundary layer for either normal or inclined injection.