Positioning of Hydrodynamic Lift Features on Non-Contacting Mechanical Gas Seal Rings

Abstract

Most analytical studies published on gas seals assume that grooved rings remain stationary while plain face rings rotate, regardless of which ring actually rotates. Indeed, examination of the simplified equations for thin fluid films reveals no difference whether the ring with the hydrodynamic lift features rotates or the plain face ring rotates, so long as rotation occurs in the proper direction for positive pressure and film stiffness generation. Suggestions have been made that differences exist between the two scenarios, especially when considering flow patterns and inertial effects of working fluid within the gas film and face grooves. In the present study, Computational Fluid Dynamics is used to examine these issues. Since the full Navier-Stokes equations are solved, simplifying assumptions become unnecessary. While the CFD results of the present study indicate the equivalency of the two rotational conditions, the details of the pressure development and velocity variations within the fluid film and face grooves of a barrier gas seal give further insight into how these seals perform.

Presented at the 54th Annual Meeting Las Vegas, Nevada May 23–27, 1999

KEY WORDS:

• Computational Fluid Dynamics
• Gas Seals
• Fluid Film

Notes

Presented at the 54th Annual Meeting Las Vegas, Nevada May 23–27, 1999