Influence of Fluid Slip on Operation Characteristics for High-Speed Spiral Groove Seal Ring

The multi-phase method applied in cavitation region believes gas and oil phase separated and oil slips over gas layer, so slip plays a role for fluid flowing in cavitation region. Spiral groove is widely applied in seal ring for its perfect hydrodynamic effect, but the cavitation is easy to occur in divergence region of groove. Therefore, influences of both cavitation and slip on operation characteristics for spiral groove seal ring at high speed have been discussed in multi-phase method. In order to attain this goal, a new hydrodynamic model based on multi-phase method, apparent local slip theory and JFO cavitation theory is built up. An accurate prediction of lubrication characteristics is represented by comparing with published experimental data. Also, the slip region is observed by a designed test and the observed results are almost the same with simulation, which further confirms the rationality of the new hydrodynamic model based on multi-phase method. The results show the cavitation ratio and area of slip region increase with the rise of speed and spiral angle. However, as to slip level, it rises with speed but decreases with spiral angle. Then, the damping and stiffness obtained from new model are compared with conventional model. Stiffness coefficient in new model is smaller than conventional model, while the damping coefficient is larger.