The fuel cell control system includes: a reactor; an air compressor, wherein the air compressor has a compressing cavity, the compressing cavity has a gas inlet and a gas outlet, a rotatable pressure wheel is disposed inside the compressing cavity, and the gas outlet is in communication with the reactor; a control flow channel, wherein a first end of the control flow channel is in communication with the gas-intake side of the pressure wheel, a second end of the control flow channel is in communication with the wheel-back side of the pressure wheel, and the control flow channel is provided with a return valve for regulating the flow rate of the control flow channel; and a central control unit, wherein the central control unit is communicatively connected to the return valve to control the opening degree of the return valve.

A turbomachine for an aircraft extending axially along an axis X comprising a primary flow path in which an air stream flows intended for the combustion chamber and a secondary flow path in which an air stream flows intended for propulsion, the compressor comprising a plurality of first variable bypass valves, a plurality of second variable bypass valves, the turbomachine comprising a first control system configured to control the movement of the plurality of first variable bypass valves and a second control system configured to control the movement of the plurality of second variable bypass valves, the first control system and the second control system being separate.

Pneumatic air systems for use onboard aircraft include a compressor configured to receive air from an air supply and increase a pressure of said received air to generate compressed air, a heat exchanger configured to receive the compressed air as a first working fluid and a treating air as a second working fluid, the heat exchanger configured to convert the compressed air to compressed and temperature treated air, one or more aircraft systems configured to receive the compressed and temperature treated air, and a surge prevention circuit arranged to prevent surge of air at the compressor, wherein the surge prevention circuit comprises a mechanical valve that is actuated based on a detected pressure within a sense line operably coupled to the mechanical valve.

A compressor is provided with: an impeller a housing configured to rotatably house the impeller and having an intake passage for introducing a gas to the impeller from outside the housing, a scroll passage for guiding the gas having passed through the impeller to the outside, and a bypass passage connecting the intake passage and the scroll passage so as to bypass the impeller; and a bypass valve having a valve body disposed in the bypass passage and capable of opening and closing the bypass passage. The valve body is configured to, in a fully closed state, separate the bypass passage into an inlet-side passage having a communication port communicating with the scroll passage and an outlet-side passage communicating with the intake passage. An inlet-side passage wall surface which defines the inlet-side passage includes at least an upstream passage wall surface portion connected to an upstream end of the communication port in a cross-sectional view of the housing taken along an axis of the impeller. The upstream passage wall surface portion is configured such that an angle between the upstream passage wall surface portion and an upstream scroll wall surface of a scroll passage wall surface which defines the scroll passage connected to the upstream end is less than 90 degrees.

A compression system includes a compressor that compresses a synthesis gas to produce a compressed gas, a first line that supplies a first gas constituting the synthesis gas to the compressor, a second line that supplies a second gas constituting the synthesis gas to the first line, a discharge line that circulates the compressed gas, a recirculation line that recirculates a part of the compressed gas from the discharge line to the first line, a first regulating valve arranged in the first line, a second regulating valve arranged in the second line, a discharge valve arranged in the discharge line, a recirculation valve arranged in the recirculation line, and a valve control device that performs switching between the first regulating valve, the second regulating valve, the discharge valve, and the recirculation valve based on an operation condition of the compressor.

Aero-acoustically damped bleed valves are disclosed. An example variable bleed valve apparatus comprises a variable bleed valve door to actuate the variable bleed valve apparatus, and a variable bleed valve port including an upstream edge and a downstream edge, the VBV port to define a secondary flowpath, the VBV door to cover the VBV port in a closed position, and a vortex device at the upstream edge of the variable bleed valve port, the vortex device including a vorticity generating feature along the upstream edge of the variable bleed valve port.

A casing treatment for a compressor includes one or more cavities in a casing disposed radially outwardly of tips of the compressor rotor blades. A liner is moveable relative to the casing between a first position and a second position. The liner is shaped to add a volume to the tip clearance gap when moving from the second position toward the first position. The liner is displaceable between the first and second positions in coordination with at least the rotation of inlet guide vanes (IGVs) between IGV positions.

A sleeve valve includes an inlet port and an outlet port. A sleeve is movable to close flow from the inlet port to the outlet port. The sleeve valve has a sleeve biased to an open position at which it allows flow from the inlet port to the outlet port by a spring. Pressure in a pressure chamber urges the sleeve to a closed position at which it blocks flow from the inlet port to the outlet port. A line pressure conduit communicates the fluid chamber into the pressure chamber. Pressurized air is supplied to the pressure chamber through a selectively closed valve. The selectively closed valve is opened to allow the flow of high pressure air from a pressure source into the pressure chamber to move the sleeve to a closed position. A bleed air system for a gas turbine engine is also disclosed.

A multistage centrifugal pump for conveying a fluid includes a pump housing with an inlet to receive the fluid and an outlet to discharge the fluid, a first stage impeller and a last stage impeller to convey the fluid from the inlet to the outlet, a shaft to rotate the first stage impeller and the last stage impeller about an axial direction, a suction chamber arranged upstream of the first stage impeller and in fluid communication with the inlet, a recirculation path for the fluid including a return opening and extending from the return opening to the suction chamber, the return opening located at or in the flow path downstream of the first stage impeller and upstream of the last stage impeller, and a flow control rod disposed in the recirculation path, the flow control rod to adjust a recirculation flow through the recirculation path into the suction chamber.

Methods, apparatus, systems, and articles of manufacture are disclosed for a variable bleed valve assembly. An example variable bleed valve assembly includes a variable bleed valve (VBV) door corresponding to a bleed port, an intermediary device operatively coupled to the VBV door, and a first actuator operatively coupled to the intermediary device, the first actuator to move between a first position and a second position, the first actuator to cause the intermediary device to move between the first position and the second position to cause the VBV door to move between the first position and the second position.