关键词: 刷式密封;ALE流固耦合;泄漏特性;刷丝运动状态;变形接触

Abstract: The existing brush seal fluid-structure interaction solution model is difficult to calculate because of mesh distortion caused by the deformation contact of brush wire. A three-dimensional transient bidirectional fluid-structure interaction solution model considering the deformation contact of brush wire based on ALE (Arbitrary Lagrange-Euler) fluid-structure interaction method was proposed. An experimental device was designed to study the leakage characteristics of brush seal and the motion trajectory of observable brush wire. The effects of the brush wire motion state on the leakage characteristics and the variation of the leakage characteristics under different pressure ratios were studied experimentally. On the basis of verifying the accuracy of the brush seal fluid-structure interaction solution model, the distribution of brush seal speed and the motion state of brush wire at different time were numerically analyzed, the influence law of different structural parameters on leakage characteristics was studied. The results show that the method based on ALE fluid-structure interaction solves the problem that the traditional brush seal solution model is difficult to calculate because of mesh distortion caused by brush wire contact, and ALE fluid-structure interaction can accurately calculate the leakage characteristics and mechanical characteristics of brush seal. Brush wire blow down will cause leakage reduction, the phenomenon of brush filament flutter mainly occurs in the front brush area at the entrance of the airflow, which will cause the leakage to increase, under the action of airflow force, the axial thickness of the brush beam becomes smaller, which is helpful to reduce the leakage. Under the condition of studying in this paper, the middle part of the brush wire fixed end and the free end deforms firstly, as time changes, the airflow velocity gradually stabilizes, the maximum velocity appears in the contact position between the end-row brush wire and the backing plate fence, the free end of the brush wire deformation is the largest. With the increasing of seal clearance, the leakage increases. Compared to the seal clearance 0mm, the leakage at the seal clearance 0.2mm increases 51.6% ~ 62.8%. With the increase of brush wire row, the leakage gradually decreases. When the number of brush wire rows is more than 25, its influence on the leakage is small. With the increasing of the brush wire clearance, the axial clearance and the protection height of the backing plate fence, the leakage quantity increases gradually and then tends to flatten.

Key words: Brush seal;ALE fluid-structure interaction;Leakage characteristic;Brush wire motion status;Deformation contact