WEAR OF BRUSH SEALS - BACKGROUND AND NEW MODELING APPROACH

The brush seal, with superior leakage performance, is emerging as a ne w sealing technology to effectively control cooling and leakage flows in gas turbine engines. Because the bristles slide against the rotor s urface, wear at the contact becomes a major concern as it determines t he life and efficiency of the seal. To optimize seal ye and efficiency , an in-depth study of the factors causing the seal stiffness is neede d, and a good choice of materials must be made. This work investigates some of the past research on brush Seal wear. Although considerable r esearch has been done on material selection. and tribopairs, the brief survey reveals the lack of reliable anal;ses to evaluate contact load s and to address heat transfer issues. The complicated nature of brist le behavior under various combinations of pressure load and rotor inte rference requires computer analysis to study the details that may not be available through analytical formulations. In an effort to meet thi s need, the present work includes a preliminary computational model of a brush seal. The model consists of a 3-D finite element model of a r epresentative brush seal segment with a mating rotor surface. Prelimin ary results from the model show reasonable agreement with actual seal behavior.