An iterative CFD and mechanical brush seal model and comparison with experimental results

The position of the bristles within a brush seal is dictated by the pressur e distribution within the seal, which is itself influenced by the position of the bristle matrix. In order to predict mass flows, pressure capabilitie s, bristle displacements, stresses, and contact loads at the rotor interfac e, a technique for iterating between a CFD and a mechanical model has been developed. The iterative technique is used to model the behavior of seals,w ith an initial build clearance, where the application of pressure causes a change in the position of the bristle matrix. Frictional effects between ne ighboring bristles and at the backing ring influence the behavior of the br istles and these are accounted for within the mechanical part of the model. Results are presented and discussed for seals of both initial build cleara nce and interference. The mathematical predictions for flow: contact loads at the rotor interface, and the nature of the bristles displacements are co mpared with experimental results.