Abstract: Sealing assemblies and systems and their assembly methods are provided. For example, a seal assembly is provided for use between an inner shaft and an outer shaft that are rotatable about a common axis. The seal assembly comprises a first end ring having an aft face; a second end ring positioned aft of the first end ring and having a forward face; a first hydrodynamic portion defined on the aft face of the first end ring; a second hydrodynamic portion defined on the forward face of the second end ring. A seal element is disposed between the first end ring and the second end ring such that the seal element is positioned between the first hydrodynamic portion and the second hydrodynamic portion.

Abstract: In one aspect, the present disclosure is directed to a bearing compartment sealing system including a bearing for supporting a shaft. A housing encloses the bearing and defines a compartment for holding lubricant therein. At least two seals are located between the shaft and the housing. The at least two seals, the housing, and the shaft collectively enclose the compartment. Only one of the at least two seals is a hydrodynamic seal.

Abstract: In one aspect, the present disclosure is directed to a bearing compartment sealing system including a bearing for supporting a shaft. A housing encloses the bearing and defines a compartment for holding lubricant therein. At least two seals are located between the shaft and the housing. The at least two seals, the housing, and the shaft collectively enclose the compartment. Only one of the at least two seals is a hydrodynamic seal.

Abstract: A sump pressurization system for a gas turbine engine comprises a first hollow shaft and a second hollow shaft disposed within the first hollow shaft and defining a cavity therebetween. Each of the first and second hollow shafts has a common axis of rotation. Also included is a source of pressurized air to pressurize the cavity and a plurality of hollow tubes disposed in the cavity. The tubes are oriented perpendicular to the axis of rotation and are connected to and rotatable with the first hollow shaft. A plurality of apertures in the second hollow shaft are in fluid communication with the tubes, such that pressurized air flowing through the tubes passes through the apertures into the interior of the second hollow shaft.

Abstract: A sump pressurization system for a gas turbine engine comprises a first hollow shaft and a second hollow shaft disposed within the first hollow shaft and defining a cavity therebetween. Each of the first and second hollow shafts has a common axis of rotation. Also included is a source of pressurized air to pressurize the cavity and a plurality of hollow tubes disposed in the cavity. The tubes are oriented perpendicular to the axis of rotation and are connected to and rotatable with the first hollow shaft. A plurality of apertures in the second hollow shaft are in fluid communication with the tubes, such that pressurized air flowing through the tubes passes through the apertures into the interior of the second hollow shaft.