Theory and experiment on the leakage characteristics of brush seals based on fluid-structure interaction

The leakage flow characteristics and the influencing factors of the brush seals were studied both theoretically and experimentally. A fluid-structure interaction theoretical model was established to analyze the leakage flow characteristics of brush seals. Experiments were presented to test the leakage quantity of brush seals with different pressure ratios and rotational speeds and compared with the theory solution model to verify. Based on the accuracy of the theory computational model, the effect law of the brush seal leakage quantity in different structural parameters was analyzed, and the formula for predicting the leakage quantity of brush seals was constructed. The results showed that, the leakage quantity of the brush seals increased approximately linearly with the increase of the pressure ratio when the radial clearance was fixed. The rotational speed had little influence on the leakage quantity of the brush seals. Bristles diameter and the clearance of the bristles affected the leakage quantity through affecting the effective flow area of the gas in the brush area, the smaller effective flow area led to the smaller leakage quantity. With the increase of the bristles diameter and the axial rows of the bristles, the leakage quantity of the brush seals decreased gradually. The leakage quantity increased with the increase of the bristles clearances. As the backing plate fence height and the axial clearance between the last row bristles and the backing plate fence increased, the leakage quantity firstly increased rapidly, and finally became stable. The constructed theoretical formula of leakage quantity can accurately predict the leakage quantity of brush seals and provide a theoretical basis for the optimization design of brush seals structure. © 2019, Editorial Department of Journal of Aerospace Power. All right reserved.