Abstract: A turbomachine engine includes a fan section having a fan shaft, and a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine includes a low-speed shaft coupled to the power turbine and having a midshaft that extends from a forward bearing to an aft bearing. The low-speed shaft is characterized by a midshaft rating (MSR) between two hundred (ft/sec)1/2 and three hundred (ft/sec)1/2. The low-speed shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). The turbomachine engine includes a gearbox assembly that couples the fan shaft to the low-speed shaft and characterized by a gearbox assembly mode less than 95% of a midshaft mode of the midshaft or greater than 105% of the midshaft mode.

Abstract: A turbomachine engine includes a fan section having a fan shaft, and a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine includes a low-speed shaft coupled to the power turbine and having a midshaft that extends from a forward bearing to an aft bearing. The low-speed shaft is characterized by a midshaft rating (MSR) between two hundred (ft/sec)½ and three hundred (ft/sec)½. The low-speed shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). The turbomachine engine includes a gearbox assembly that couples the fan shaft to the low-speed shaft and characterized by a gearbox assembly mode less than 95% of a midshaft mode of the midshaft or greater than 105% of the midshaft mode.

Abstract: A thrust bearing assembly for a machine includes a stator housing, a fluid film thrust bearing, and a ring bearing. The stator housing surrounds at least a segment of a rotor shaft and one or more runners on the rotor shaft that include a first runner surface and a second runner surface facing in opposite axial directions along the rotor shaft. The fluid film thrust bearing is axially held between a first stator surface of the stator housing and the first runner surface. The fluid film thrust bearing is configured to generate a fluid cushion that blocks the first runner surface from engaging the fluid film thrust bearing. The ring bearing is axially held between a second stator surface of the stator housing and the second runner surface. The ring bearing has an annular contact surface that engages the second runner surface to axially support the rotor shaft.

Abstract: A thrust bearing assembly for a machine includes a stator housing, a fluid film thrust bearing, and a ring bearing. The stator housing surrounds at least a segment of a rotor shaft and one or more runners on the rotor shaft that include a first runner surface and a second runner surface facing in opposite axial directions along the rotor shaft. The fluid film thrust bearing is axially held between a first stator surface of the stator housing and the first runner surface. The fluid film thrust bearing is configured to generate a fluid cushion that blocks the first runner surface from engaging the fluid film thrust bearing. The ring bearing is axially held between a second stator surface of the stator housing and the second runner surface. The ring bearing has an annular contact surface that engages the second runner surface to axially support the rotor shaft.

Abstract: A seal assembly for a rotary machine includes plural seal segments disposed circumferentially intermediate to a stationary housing and a rotor. One or more of the seal segments includes a stator interface element, a radially oriented front cover plate, and a movably supported shoe plate. The shoe plate includes one or more labyrinth teeth forming a primary seal with the rotor, a load bearing surface radially offset from the one or more labyrinth teeth, a radial surface forming a frictionless secondary seal with the front cover plate, and one or more internal passageways configured to direct fluid through the shoe plate or through the front cover plate, and between the radial surface of the shoe plate and the front cover plate to form the frictionless secondary seal.