Simulation of flow and heat transfer in the tip region of a brush seal

Abstract

This study considers the flow between the bristle tips and the rotor of an idealised brush seal. CFD results show that the `air-riding' effect thought by other workers to have occurred in their experiments may be produced by tilting of the bristle tip surface relative to the rotor. This tilting may occur in practice as the rotor-to-stator clearance increases and the bristles are blown down onto the rotor. CFD solutions are obtained for cases with and without angled tips, assuming either rectangular or hexagonal bristle packing, and both with and without axial flow. Various tip angles and minimum tip-to-rotor clearances are considered, and the trends found are compared with theoretical results for 2D, low Reynolds number flow. The most complete model presented includes heat conduction in the models and heat generation due to contact friction.