A turbocharger includes a housing and a rotating group supported for rotation within the housing. The rotating group includes a compressor wheel disposed within a compressor section of the turbocharger, and the rotating group includes a turbine wheel disposed within a turbine section of the turbocharger. The turbine wheel includes a bleed pressure surface. The turbocharger further includes a bleed passage that extends at least partly through the housing to fluidly connect the compressor section to the turbine section. The bleed passage is configured to direct a bleed flow of fluid from the compressor section to the bleed pressure surface to supply a thrust counterbalance load to the bleed pressure surface.

A circumferential seal assembly capable of separating a gas into two separate flow paths before communication between a rotatable runner and a pair of seal rings is presented. The seal assembly includes an annular seal housing, a pair of annular seal rings, a rotatable runner, and a plurality of groove structures. The seal housing is interposed between a pair of compartments. The seal rings are separately disposed within the seal housing and separately disposed around the rotatable runner. The groove structures are disposed along an outer annular surface of the rotatable runner. A gas is communicable onto the groove structures. Each groove structure includes at least two hydrodynamic grooves that separate and communicate the gas onto the seal rings. Each groove includes steps whereby the depth of at least one adjoining step decreases in the direction opposite to rotation with or without the depth of another adjoining steps increasing in the direction opposite to rotation.

A circumferential seal assembly capable of separating a gas into two separate flow paths before communication between a rotatable runner and a pair of seal rings is presented. The seal assembly includes an annular seal housing, a pair of annular seal rings, a rotatable runner, and a plurality of groove structures. The seal housing is interposed between a pair of compartments. The seal rings are separately disposed within the seal housing and separately disposed around the rotatable runner. The groove structures are disposed along an outer annular surface of the rotatable runner. A gas is communicable onto the groove structures. Each groove structure includes at least two hydrodynamic grooves that separate and communicate the gas onto the seal rings. Each groove includes steps whereby the depth of at least one adjoining step decreases in the direction opposite to rotation with or without the depth of another adjoining steps increasing in the direction opposite to rotation.

A power module includes a turbine arranged along a rotation axis, an interconnect shaft fixed in rotation relative to the turbine, and a compressor with a regenerative compressor wheel. The regenerative compressor wheel is fixed in rotation relative to the interconnect shaft supported for rotation with the turbine about the rotation axis. Generator arrangements, unmanned aerial vehicles, and methods of generating electrical power are also described.

A bearing includes a thrust gas bearing attached to a journal bearing and two or more converging-diverging orifices defined in a surface of at least one of the thrust gas bearing and the journal bearing. The converging-diverging orifices supply at least one pressurized gas to an interior of the bearing. Hydrodynamic lifting grooves are provided on the faces of the thrust gas bearing and the journal bearing and provide improved load capacity and sealing capabilities. Control over the ratios of the pressurized gases provides for additional sealing capabilities and reduced leakage. A metal mesh damper provides increased damping of the gas bearing.

Each of foils (22) includes: a top foil portion (22a) including a bearing surface (S); and a back foil portion (22b), which is formed on an upstream side of the top foil portion (22a), and is arranged so as to overlap behind the top foil portion (22a) of the adjacent foil (22) (on a side opposite to the bearing surface (S)). An angle (E) covering a radially inner end of an overlapping portion (P) between the adjacent foils (22) is smaller than an angle (D) covering a radially outer end of the overlapping portion (P).

A circumferential seal assembly suitable for forming a thin film between a rotatable runner and a sealing ring is presented. The assembly includes an annular seal housing, a rotatable runner, an annular seal ring, and a plurality of groove structures. Each groove structure includes a groove and an optional feed groove. The groove includes at least two adjoining steps defined by base walls arranged to decrease depthwise. Two adjoining base walls are disposed about a base shoulder. Each base shoulder locally redirects a longitudinal flow to form an outward radial flow in the direction of the annular seal ring. The base walls are bounded by and intersect a pair of side walls. A side wall includes at least one side shoulder which narrows the groove widthwise and locally redirects the longitudinal flow to form a lateral flow in the direction of the other side wall. Outward and lateral flows separately or in combination enhance stiffness of a thin-film layer between the annular seal ring and the rotatable runner.

A circumferential seal assembly suitable for forming a thin film between a rotatable runner and a sealing ring is presented. The assembly includes an annular seal housing, a rotatable runner, an annular seal ring, and a plurality of groove structures. Each groove structure includes a groove and an optional feed groove. The groove includes at least two adjoining steps defined by base walls arranged to decrease depthwise. Two adjoining base walls are disposed about a base shoulder. Each base shoulder locally redirects a longitudinal flow to form an outward radial flow in the direction of the annular seal ring. The base walls are bounded by and intersect a pair of side walls. A side wall includes at least one side shoulder which narrows the groove widthwise and locally redirects the longitudinal flow to form a lateral flow in the direction of the other side wall. Outward and lateral flows separately or in combination enhance stiffness of a thin-film layer between the annular seal ring and the rotatable runner.

A power module includes a turbine arranged along a rotation axis, an interconnect shaft fixed in rotation relative to the turbine, and a compressor with a regenerative compressor wheel. The regenerative compressor wheel is fixed in rotation relative to the interconnect shaft supported for rotation with the turbine about the rotation axis. Generator arrangements, unmanned aerial vehicles, and methods of generating electrical power are also described.

A circumferential seal assembly suitable for forming a thin film between a rotatable runner and a sealing ring is presented. The assembly includes an annular seal housing, a rotatable runner, an annular seal ring, and a plurality of groove structures. Each groove structure includes a groove and an optional feed groove. The groove includes at least two adjoining steps defined by base walls arranged to decrease depthwise. Two adjoining base walls are disposed about a base shoulder. Each base shoulder locally redirects a longitudinal flow to form an outward radial flow in the direction of the annular seal ring. The base walls are bounded by and intersect a pair of side walls. A side wall includes side shoulders which narrows the groove widthwise and locally redirects the longitudinal flow to form a lateral flow in the direction of the other side wall. Outward and lateral flows separately or in combination enhance stiffness of a thin-film layer between the annular seal ring and the rotatable runner.