Study on the friction and wear performance of the micro-surface textured face seal under the water-lubricated conditions

Due to the poor lubricated performance of the low-viscosity lubricants (such as liquid oxygen and liquid hydrogen), the severe friction and wear of the seal’s pair for the high-speed turbopump in the cryogenic liquid rocket engine often occur, which may lead to the seal failure (excessive leakage or serious wear). For improving the tribological properties of the seal, the seal’s rotor with the micro-surface texture is proposed and the friction and wear performance of the seal pairs are studied. First, the theoretical model for solving the performance of the micro-surface textured face seal is developed. Second, the optimized structural parameters (dimple diameter, grooved area ratio and the dimple depth–diameter ratio) for the micro-surface texture are obtained, and the laser surface texturing method is applied to make the samples of the rotor. Third, the tribological properties of the micro-surface textured sealing ring are tested by the pin-disk tribology tester, and the comparisons between the friction coefficients and wear rate of the textured rotor ring and that of the ordinary steel disk and disk with the DLC coating are finished. The results show that optimized dimple diameter, grooved area ratio and the dimple depth–diameter ratio are 50 μm, 0.6 and 1, respectively, and the friction coefficients of the proposed rotor are 0.17 and 0.36, respectively, under the dry friction and water-lubricated conditions. The study is of great theoretical and experimental reference for designing the face seal under the low-temperature, low-viscosity and high-speed conditions in the cryogenic liquid rocket engine.