| 摘要 |
<p>To restrict fluid flow between a high pressure working gas region and a low pressure lubricating oil sump in a gas turbine engine, a fluid bearing face seal includes a rotating mating ring (10) confronted by a non-rotating carbon sealing ring (12) with a face machined to provide an annular array of alternating lands and liftoff force-generating hydrodynamic lift pads (24), each comprising a three-step stairwell radially inwardly and outwardly bound by rails flush with the lands. An improved secondary seal includes a carbon mating ring to reduce seating drag forces on a piston ring biased into sealing engagement with a sealing ring carrier and a plurality of fluid orifices for pressure moment balancing the piston ring to the working gas pressure. To generate additional liftoff forces at low mating ring angularly velocities, the sealing ring face may also include an annular hydrostatic lift pad. <IMAGE></p> |
