Numerical study on leakage flow characteristics of carbon fiber brush seal between counter-rotating shafts

There are higher requirements for the seal performance and service life of the sealing structure between counter-rotating shafts of the aero-engine. The structure of carbon fiber rotating brush seal between rotating shafts was proposed. Based on the theory of bristles centrifugal effect mechanics and porous media theory, the method of bristles shape variable correction porosity and resistance coefficient was used to establish a solution model for the leakage flow characteristics of carbon fiber rotating brush seal between rotating shafts. The influence of bristle lay angle, bristle diameter and rotating speed on the mechanical deformation characteristics of carbon fiber bristles was analyzed, and the leakage flow characteristics of brush seal between rotating shafts were studied. The results showed that the deformation and rotation angle of the bristle could increase by increasing the speed of the inner rotor, reducing the diameter of the bristle and increasing the bristle lay angle. Considering the centrifugal effect of the bristles, when the inner rotor speed was 3230 r/min, the deformation of the T650 carbon fiber bristles in the radial direction of the shaft was 16.43% of the deformation of the Haynes25 bristles. When the inner rotor speed was 10000 r/min, the bristle lay angle increased from 30° to 45°, and the radial deformation of the bristles on the shaft was increased by 104.02%. Under the same working conditions, the fine-diameter bristles sealing effect was better. When the contact gap between the bristles and the outer rotor was 0 mm, the bristle diameter was reduced from 0.07 mm to 0.05 mm, and the leakage was reduced by 12.42%.