The position of the bristles within a brush seal is dictated by the pressure distribution within the seal, which is itself influenced by the position of the bristle matrix. In order to predict mass flows, pressure capabilities, bristle displacements, stresses and contact loads at the rotor interface a technique for iterating between a CFD and a mechanical model has been developed. The iterative technique is used to model the behaviour of seals with an initial build clearance, where the application of pressure causes a change in the position of the bristle matrix. Frictional effects between neighbouring bristles and at the backing ring influence the behaviour of the bristles and these are accounted for within the mechanical part of the model. Results are presented and discussed for seals of both initial build clearance and interference. The mathematical predictions for flow, contact loads at the rotor interface and the nature of the bristles displacements are compared with experimental results.

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