The influence of spiral angle on lift-off speed of face gas seal under start-up

Abstract

The lift-off rotating speed of dry gas seal (SG-DGS) is investigated by conducting an experimental test, and using a theoretical model based on the slip-flow effect. The experimental results show that the mixed lubrication regime is transferred to the hydrodynamic lubrication regime at a smaller lift-off rotational speed for a lower spiral angle. On the other hands, the theoretical procedure is implemented to calculate the gas film opening force and the lift-off rotational speed is determined by the minimum contact gas film thickness. The theoretical results show that the smaller spiral angle can offer the greater gas film force and lower lift-off speed. Meanwhile, the experimental data verify the theoretical results well. It can be demonstrated that the spiral angle has a strong effect on the lift-off rotating speed and the theoretical model can calculate the lift-off rotational speed of SG-DGS during start-up process.

Effect of Laminar, Turbulent and Slip Conditions on the Dynamic Coefficients of a Dry Gas Seal

“…In Table 1, G r , G θ , and q p are radial turbulent coefficient, circumferential turbulent coefficient, and slip coefficient defined in Equations ( 2)-( 4), and Table 2 [1,[16][17][18][19][20][21][22][23][24]:…”