An apparatus for sealing such a gap may be a plunger seal which may include a flap arm comprising resilient sheets and a wall arm comprising resilient sheets. A proximal end portion of the flap arm may include a closeout seal coupled to the flap. A proximal end portion of the wall arm may include a plunger having a geometry corresponding to that of the closeout seal so the plunger may be matingly received by the closeout seal. When positioned in a gap, the plunger seal may exert a force to urge the flap arm towards the flap and to urge the wall arm and resilient sheet towards the structure to seal the gap.

A seal system includes a ceramic component, a metallic component, a silicon-containing layer, and a barrier layer. The ceramic component has a first surface region that defines a first surface roughness. The metallic component is situated adjacent to the first surface region and has a second surface region facing the first surface region. The silicon-containing layer is on the first surface region of the ceramic component and has a contact surface that defines a second surface roughness which is less than the first surface roughness. The barrier layer is on the metallic component and in contact with the silicon-containing layer and serves to limit interaction between silicon of the silicon-containing layer and the metallic component. The barrier layer includes at least one of alumina or MCrAlY.

A split labyrinth seal assembly having split stationary and rotary sealing elements, and a split clamping mechanism. The clamping mechanism is configured to secure the rotary element to a rotating shaft. The rotary element can also include an integrally formed valve element that moves between a contacting and a non-contacting position in response to rotation of the shaft. The rotary element and the clamping mechanism can have surface features associated therewith to promote nesting between the components.

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.

A labyrinth seal, has: rotating and static components rotatable relative to one another relative to a central axis, the rotating component securable to a shaft via a tight fit engagement at an engagement location on the rotating component, the static component securable to a housing; teeth protruding from one of the rotating and static components towards a seal land defined by the other one of the rotating and static components; and clearances between the teeth and the seal land, a first clearance of the clearances greater than a second clearance of the clearances, the first clearance located closer to the engagement location of the rotating component than the second clearance.

A turbine section has: a rotor rotatable about a central axis, the rotor having blades each protruding radially outwardly from a platform relative to the central axis; a stator having vanes each protruding radially outwardly from a shroud; a rim seal between the platform and the shroud, the rim seal having: an axial overlap between the platform and the shroud, and a lip protruding in a direction having a radial component relative to the central axis from one of the platform and the shroud toward the other of the platform and the shroud, the lip axially overlapping the other of the platform and the shroud, the lip having a radial height such that a radial gap remains between the lip and the other of the platform and the shroud when the turbine section is in operation.

A method to produce a ceramic matrix composite with controlled surface characteristics includes: applying a scrim ply to a surface of a fiber preform, where the fiber preform includes silicon carbide fibers coated with boron nitride; infiltrating the fiber preform and the scrim ply with a slurry, thereby forming an impregnated ply on an impregnated fiber preform; infiltrating the impregnated fiber preform and the impregnated ply with a melt comprising silicon, and then cooling, thereby forming a ceramic matrix composite having a ceramic surface layer thereon, where the ceramic surface layer has a predetermined thickness and is devoid of boron; machining or grit blasting the ceramic surface layer to form an intermediate layer suitable for coating; and depositing an environmental barrier coating on the intermediate layer. Thus, a ceramic matrix composite coated with the environmental barrier coating is formed with the intermediate layer in between.

A sealing apparatus for a gas turbine engine includes: a first component; a second component positioned in proximity to the first component such that cavity is defined between the first and second components; a resilient seal disposed in the cavity so as to block gas flow between the first and second components, the resilient seal having a first contact surface contacting the first component and a second contact surface contacting the second component; and wherein the resilient seal is configured so as to produce a rolling movement in response to relative movement of the first and second components.

An assembly is provided for a turbine engine. This turbine engine assembly includes a first rotating structure, a turbine engine apparatus, a rotating coupler and a seal assembly. The first rotating structure is configured to rotate about a rotational axis. The turbine engine apparatus includes an electric machine and a second rotating structure. The electric machine includes an electric machine rotor and an electric machine stator. The second rotating structure is configured to rotate about the rotational axis and is coupled to the electric machine rotor. The rotating coupler is coupled to the first rotating structure by a first connection. The rotating coupler is coupled to the second rotating structure by a second connection. The seal assembly includes a rotating seal land and a stationary seal element. The rotating seal land is mounted onto the rotating coupler. The stationary seal element sealingly engages the rotating seal land.

An air cycle machine includes an air inlet connected to an air cycle compressor. Air downstream of the air cycle compressor is connected to be delivered across a first turbine. The air cycle compressor is driven by the first turbine through a shaft. Air downstream of the first turbine is connected to a second turbine. The second turbine is connected to deliver air downstream. The second turbine is connected with a second shaft to drive a fan rotor. The fan rotor delivers a source of air across a primary heat exchanger positioned between the inlet and the air cycle compressor. The air cycle compressor and the first turbine are formed of a metal. The second turbine and the fan rotor are formed of non-metallic materials.