An airfoil assembly includes an airfoil fairing, a spar, a seal plate, and a seal. The airfoil fairing has a fairing platform and a hollow airfoil section that extends from the fairing platform. The spar has a spar leg that extends in the hollow airfoil section. The spar leg defines a spar leg periphery. The seal plate is secured with the fairing platform. The seal plate has an opening, and the opening has an opening periphery that is complementary to the spar leg periphery. The spar leg extends through the opening. The seal is between the seal plate and the spar leg. The seal seals around the spar leg periphery.

A system for modulating air flow in a gas turbine engine is provided. The system may include a seal wall comprising an opening, a seal door configured to slideably engage the seal wall, and an actuator configured to move the seal door over the opening. In various embodiments, the system may include a surface forward of the seal door. The seal door may be configured to seal a passage through the surface and the opening of the seal wall. A track may be disposed under the seal door. The track may comprise cobalt. Rollers may be coupled to the seal door with the rollers on the track. The seal door may comprise a nickel-chromium alloy. A sync ring may be coupled to the seal door. The actuator may be coupled through the sync ring to the seal door.

A system for modulating air flow in a gas turbine engine is provided. The system may include a seal wall comprising an opening, a seal door configured to slideably engage the seal wall, and an actuator configured to move the seal door over the opening. In various embodiments, the system may include a surface forward of the seal door. The seal door may be configured to seal a passage through the surface and the opening of the seal wall. A track may be disposed under the seal door. The track may comprise cobalt. Rollers may be coupled to the seal door with the rollers on the track. The seal door may comprise a nickel-chromium alloy. A sync ring may be coupled to the seal door. The actuator may be coupled through the sync ring to the seal door.

The amount of consumption of gas is reduced when the gas is expanded to be cooled by using a plurality of expansion turbines. A high-pressure expansion turbine includes: a gas supply passage through which bearing gas is supplied to a bearing portion; and a gas discharge passage through which the bearing gas which has been supplied from the gas supply passage to the bearing portion is discharged from the bearing portion. A low-pressure expansion turbine includes: a gas supply passage through which the bearing gas is supplied to a bearing portion; and a gas discharge passage through which the bearing gas which has been supplied from the gas supply passage to the bearing portion is discharged from the bearing portion. The bearing gas discharged from the gas discharge passage of the high-pressure expansion turbine is supplied to the gas supply passage of the low-pressure expansion turbine.

The amount of consumption of gas is reduced when the gas is expanded to be cooled by using a plurality of expansion turbines. A high-pressure expansion turbine includes: a gas supply passage through which bearing gas is supplied to a bearing portion; and a gas discharge passage through which the bearing gas which has been supplied from the gas supply passage to the bearing portion is discharged from the bearing portion. A low-pressure expansion turbine includes: a gas supply passage through which the bearing gas is supplied to a bearing portion; and a gas discharge passage through which the bearing gas which has been supplied from the gas supply passage to the bearing portion is discharged from the bearing portion. The bearing gas discharged from the gas discharge passage of the high-pressure expansion turbine is supplied to the gas supply passage of the low-pressure expansion turbine.

Systems and methods for delivering a buffer fluid to a shaft seal of a gas turbine engine are provided. An exemplary system includes, a buffer fluid source, one or more first conduits providing fluid communication between the buffer fluid source and the shaft seal along a first route, and one or more second conduits providing fluid communication between the buffer fluid source and the shaft seal along a second route different from the first route. A heat exchanger is also disposed along the first route to facilitate heat transfer between buffer fluid in the one or more first conduits and a cooling fluid.

Systems and methods for delivering a buffer fluid to a shaft seal of a gas turbine engine are provided. An exemplary system includes, a buffer fluid source, one or more first conduits providing fluid communication between the buffer fluid source and the shaft seal along a first route, and one or more second conduits providing fluid communication between the buffer fluid source and the shaft seal along a second route different from the first route. A heat exchanger is also disposed along the first route to facilitate heat transfer between buffer fluid in the one or more first conduits and a cooling fluid.

Methods, apparatus, systems and articles of manufacture are disclosed. An inner shroud damper for a gas turbine engine includes: at least one carrier including a joint to couple to an inner shroud, the at least one carrier having a first side and a second side, and at least one mass damper coupled to the at least one carrier.

Methods, apparatus, systems and articles of manufacture are disclosed. An inner shroud damper for a gas turbine engine includes: at least one carrier including a joint to couple to an inner shroud, the at least one carrier having a first side and a second side, and at least one mass damper coupled to the at least one carrier.

A system for modulating air flow in a gas turbine engine is provided. The system may include a seal wall comprising an opening, a seal door configured to slideably engage the seal wall, and an actuator configured to move the seal door over the opening. In various embodiments, the system may include a surface forward of the seal door. The seal door may be configured to seal a passage through the surface and the opening of the seal wall. A track may be disposed under the seal door. The track may comprise cobalt. Rollers may be coupled to the seal door with the rollers on the track. The seal door may comprise a nickel-chromium alloy. A sync ring may be coupled to the seal door. The actuator may be coupled through the sync ring to the seal door.