Bristle deflections have important influence on the flow field characteristic and mechanical characteristic. The problems of the leakage

hysteresis and bristle fracture produced by the deflections of bristle are very prominent. The flow field characteristic and dynamic characteristic in brush seal were predicted using a three-dimensional computational model with consideration of bristle deflections depending on two-way fluid-structure interaction and moving grids techniques. Firstly

based on the cantilever beam theory

the mechanics model of bristle was analyzed. Secondly

based on the fluid solid coupling method verified with the theoretical model and experimental results

the flow field characteristic

the law of bristle deflections

the mechanical characteristic and hysteresis characteristic were predicted. The research results show that the bristle deflections caused by forward flow impact is oscillating gradually

and the maximum stress of the bristle root is also oscillating gradually depending on the bristle deflections. Bristle deflections increase the clearance between the bristle and the rotor surface

which leads to the increases of leakage; as the bristle row number increases

the leakage decreases rapidly

then decreases slowly

and finally tends to be a stable value. The increase of the axial clearance between the last row bristle and the back plate makes the relative pressure coefficient decrease

and the axial clearance can effectively reduce the hysteresis characteristic.