A turbofan engine includes a propulsor section that has a propulsor shaft in driving engagement with a propulsor. An epicyclic gear system has a gear mesh lateral stiffness and a gear mesh transverse stiffness. A gear system input defines a gear system input lateral stiffness and a gear system input transverse stiffness. The gear system input lateral stiffness is less than 5% of the gear mesh lateral stiffness. A first turbine section rotates at a first speed, and a second turbine rotates at a second speed that is faster than the first speed. A first performance quantity is defined as the product of the first speed squared and the first area of the first turbine, a second performance quantity is defined as the product of the second speed squared and the second area of the second turbine, and a performance quantity ratio is between 0.5 and 1.5.

A gas turbine engine according to an example of the present disclosure includes, among other things, a fan shaft configured to drive a fan, a support configured to support at least a portion of the fan shaft, the support defining a support transverse stiffness and a support lateral stiffness, a gear system coupled to the fan shaft, and a flexible support configured to at least partially support the gear system. The flexible support defines a flexible support transverse stiffness with respect to the support transverse stiffness and a flexible support lateral stiffness with respect to the support lateral stiffness. The input defines an input transverse stiffness with respect to the support transverse stiffness and an input lateral stiffness with respect to the support lateral stiffness.

An air cycle machine is provided. The air cycle machine can be included an environmental control system of an aircraft. The air cycle machine can include a turbine comprising a plurality of inlet gas flow paths, a compressor driven by the turbine from a shaft, and a fan driven by the turbine from the shaft.

An electric fan for producing thrust to propel an aircraft is disclosed. The electric fan comprises a stator, a fan rotor rotatably mounted relative to the stator and an electric motor mounted to the stator and drivingly engaged with the fan rotor to cause rotation of the fan rotor relative to the stator. The fan rotor comprises an annular body defining a flow passage therethrough and a plurality of fan blades disposed in the flow passage and mounted for common rotation with the annular body about a fan rotation axis. The electric motor has a motor rotation axis that differs from the fan rotation axis.

A charge gas compressor train for an ethylene plant includes: a steam turbine; and a compression unit that is configured to be driven by the steam turbine to compress a charge gas. The compression unit includes a closed impeller at each impeller of a plurality of compression stages. An outer diameter of blades of the closed impeller at least at an initial stage of the plurality of compression stages is 1,400 to 1,800 mm. A maximum operating peripheral speed of the blades of the closed impeller at the initial stage at an outermost diameter position is 350 to 400 m/s. An output of the charge gas compressor train is 100 to 140 MW.

An electric fan for producing thrust to propel an aircraft is disclosed. The electric fan comprises a stator, a fan rotor rotatably mounted relative to the stator and an electric motor mounted to the stator and drivingly engaged with the fan rotor to cause rotation of the fan rotor relative to the stator. The fan rotor comprises an annular body defining a flow passage therethrough and a plurality of fan blades disposed in the flow passage and mounted for common rotation with the annular body about a fan rotation axis. The electric motor has a motor rotation axis that differs from the fan rotation axis.

A centrifugal gas compressor fed with a gas and a processing liquid comprises a rotor rotated by a prime mover. The rotor defines an internal axial cavity with a cylindrical surface, an annular peripheral collection cavity, and a tapered radial channel fluidly connecting the internal axial cavity and the annular peripheral collection cavity. With each rotation of the rotor, a portion of the processing fluid is swept into the inlet of the tapered radial channel and travels radially as a fluid piston under centrifugal force pushing and compressing a column of gas entrained in front of said fluid piston, and is expelled into the annular peripheral collection cavity where it undergoes centrifugal separation, leaving the compressed gas to be drawn off through the compressed gas outlet for downstream use. A method for compressing a gas is also provided.

A compressor section for a gas turbine engine according to an example of the present disclosure includes, among other things, a low pressure compressor including a plurality of rotor blades arranged about an axis, a high pressure compressor, and a core flowpath passing through the low pressure compressor. The core flowpath at the low pressure compressor defines an inner diameter and an outer diameter relative to the axis. The outer diameter has a slope angle relative to the axis.

A turbofan engine includes a fan section that drives air along a bypass flow path in a bypass duct. An epicyclic gear system in driving engagement with the fan shaft and has a gear mesh lateral stiffness and a gear mesh transverse stiffness. A gear system input to the gear system defines a gear system input lateral stiffness and a gear system input transverse stiffness. The gear system input lateral stiffness is less than 5% of the gear mesh lateral stiffness. A first performance quantity is defined as the product of a first speed squared and a first area and a second performance quantity is defined as the product of a second speed squared and a second area. A performance quantity ratio of a first performance quantity to a second performance quantity is between 0.5 and 1.5.

A turbine section of a turbomachine includes a housing that houses and supports the rotating group for rotation about an axis. The housing defines a circumferential inlet passage that extends about the axis. The housing defines a turbine wheel upstream area that is disposed downstream of the circumferential inlet passage and upstream of the turbine wheel. The housing defines an outlet that is downstream of the turbine wheel. Furthermore, the turbine section includes a first flow path that extends from the circumferential inlet passage, through the turbine wheel upstream area, across the turbine wheel, to the outlet. Moreover, the turbine section includes a recirculation flow path that extends from the circumferential inlet passage, through the turbine wheel upstream area, and back to the circumferential inlet passage.