Using a three-dimensional tube bundle model to investigate the leakage flow characteristics of the rotating brush seal

Abstract

In comparison to the traditional brush seal, the rotating brush seal installed on a rotating shaft eliminates the influence of friction heat effects and improves the operational stability of the rotating shaft system. Relevant investigations give sparse detailed parameters and experimental data for the rotating brush seal providing insufficient data support and prompting further investigation for the sealing characteristics of the rotating brush seal. In this article, the three-dimensional tube bundle model was regarded as the computational fluid domain of the rotating brush seal. The multi-block structured mesh was applied to discrete the computational domain. The effect of the pressure ratio and rotational speed on the leakage flow and aerodynamic characteristics of the brush seal were numerically investigated using three-dimensional Reynolds-Averaged Navier-Stokes solutions and $k-\omega SST$ turbulence model. Similar to the traditional brush seal, the leakage flow rate of the rotating brush seal increases linearly with the pressure ratio. The effect of the pressure ratio on the flow coefficient is more significant at low pressure ratio. When the pressure ratio increases from 1.5 to 2.5, the flow coefficient increases by 44.40%. However, when the pressure ratio increases from 3.5 to 4.5, the flow coefficient just increases by 4.12%. It means that the flow coefficient shows a trend independent of the pressure ratio at higher pressure ratio. The flow coefficient obtained by computational fluid dynamics model is found to increase lightly as the rotational speed increases. The rear bristles are subjected to large axial aerodynamic force and are prone to axial deformation. The investigation provides the reference for the performance analysis and design of rotating brush seal.