Effect of snake-biomimetic surface texture on finger sealing performance under hydrodynamic lubrication

Abstract

In recent years, surface textures have been found with extraordinary potential to improve lubrication of friction pairs, reduce viscosity, and improve wear resistance. To study the effects of surface textures in the finger sealing, as inspired by the snakeskin, four texture forms with different layouts are presented in this paper and comprehensive performance analysis is carried out under the condition of hydrodynamic lubrication. First, a numerical model of finger seals with surface textures under hydrodynamic lubrication is proposed based on the Reynolds equation. Then, finger seal performance analysis is carried out considering different texture surfaces in terms of forms, layouts, and geometric parameters. The results show that: (1) When the texture profile is consistent with the direction of rotor motion, it is beneficial to create better hydrodynamic pressure and improve sealing performance; (2) To achieve good friction and wear resistance of a textured finger seal, the texture depth should be as shallow as possible (<25 μm); (3) When the texture depth is equal to the seal clearance, the average dimensionless pressure reaches the greatest with smallest friction coefficient; (4) With the increase of the texture density, the average dimensionless pressure increases rapidly first and then gradually flattens, while the friction coefficient performs oppositely. Given the manufacturing economy, the suitable texture density is around 20% ∼ 40%.