In order to reduce the rotating stall onset flowrate, this centrifugal compressor comprises: a vaneless diffuser (12) provided on a discharge outlet (6B) side of an impeller (6); and a fluid circulation flow path (21) having an inlet (21A) that opens into a first wall section (22) of a hub casing (2B) forming the vaneless diffuser (12) and also having an outlet (21B) that opens into a second wall section (23) of the hub casing (2B) facing a hub disk (6C) rear surface in the impeller (6). As a result of causing the first wall section (22) to protrude on to a wall section (31) side of the shroud casing (2A), the flow path width (D) of the vaneless diffuser (12) is smaller than the width (W) of the discharge outlet (6B) in the impeller (6). In addition, the hub casing (2B) comprises an inclined wall section (24) having a protruding end (24A) between the discharge outlet (6B) of the impeller (6) and the inlet of the vaneless diffuser (12), said inclined wall section (24) connecting the second wall section (23) and the first wall section (22).

A shroud configured to be disposed around an impeller of a centrifugal compressor, the shroud has a wall extending around a central axis of the centrifugal compressor, the wall having an inner face oriented toward a gaspath and an outer face oriented away from the gaspath, a slot extending all around the central axis and from the inner face to the outer face of the wall, bridges secured to the wall, the bridges circumferentially distributed around the central axis and spanning across the slot, the bridges extending from roots to tips, the tips of the bridges circumferentially offset from the roots relative to the central axis.

A system includes a dynamic compressor, a variable frequency drive (VFD), and a controller. The dynamic compressor includes a motor having a driveshaft rotatably supported within the dynamic compressor, and a compression mechanism connected to the driveshaft and operable to compress a working fluid upon rotation of the driveshaft. The VFD includes a sensor configured to sense a current provided to the motor. The controller is connected to the motor and includes a processor and a memory. The memory stores instructions that program the processor to operate the motor using the VFD to compress the working fluid, receive signals representing the current from the VFD to the motor, and determine when a surge event has occurred based at least in part on the received signals representing the current from the VFD to the motor.

A coolant system includes a multistage compressor having a plurality of surge detection sensors. A condenser is connected to an outlet of the multistage compressor. An economizer is connected to an outlet of the condenser and has a gaseous coolant outlet and a liquid coolant outlet. The liquid coolant outlet is connected to a cooler and the gaseous coolant outlet is connected to a second or later stage of the multistage compressor via a controllable valve. A controller is communicatively coupled to the surge detection sensors and the controllable valve. The controller includes a non-transitory medium storing instructions for causing the controller to detect an occurrence of a surge and restricting a flow through the controllable valve until the surge has ceased.

A valve flap device for opening and closing a bypass valve of a turbocharger is provided. The valve flap device includes a valve spindle, a flap support arranged on the valve spindle and having a through aperture, a cover disk in the form of a circular ring, and a valve flap arranged on a support lower side of the flap support on the support lower side. The valve flap includes a flap plate and a flap support pin arranged on the flap plate rear side and is passed through the through aperture of the flap support and is firmly connected to the cover disk. A spring element is installed in the spring gap under a preload. A centering device, provided on the support upper side, is arranged concentrically with the central axis of the through aperture and keeps the spring element in a centered position relative to the central axis.

In an aircraft gas turbine engine equipped with a bleed-off valve that bleeds intake air compressed by a compressor exterior and an electric actuator that drives the valve when current is supplied, a required valve opening θr and a current value Ia corresponding thereto are calculated and Ia is supplied to the actuator to bring valve opening θ to the required opening θr. Then Ia is compared with a current value Ib and if Ia exceeds 1b, the valve is estimated to have failed and another current value Ic is calculated and Ic is supplied to enlarge valve opening toward wide-opening θw. Then a current value Id is calculated and supplied to decrease valve opening toward θr. Next, Id is compared with Ib and the valve is determined normal when Id is equal to or smaller than 1b. If not, it is determined to be faulty.

A compression system comprises a compressor, an inlet duct, a throttling valve installed in the inlet duct, an outlet duct, an anti-surge valve fluidly coupling the outlet duct with a portion of the inlet duct downstream of the throttling valve and a recycle valve fluidly coupling the outlet duct with a portion of the inlet duct upstream of the throttling valve. Keeping the recycle valve open, the anti-surge valve closed and the throttling valve partially closed allows lowering the pressure of the flow entering the compressor during its start-up.

A system and method for supplying compressed air from an auxiliary power unit to a main engine starter motor. The inlet guide vanes are controlled using either first or second inlet guide vane control logic and the surge control valve is controlled using either first or second surge control valve control logic. When the first inlet guide vane control logic is used, the inlet guide vanes are positioned based on a demand signal, when the second inlet guide vane control logic is used, the inlet guide vanes are positioned based on a demand schedule, when the first surge control valve logic is used, the surge control valve can be commanded to repeatedly move to only a fully-closed position and a fully-open position, and when the second surge control valve logic is used, the surge control valve can be commanded to the fully-closed position only when maximum flow is commanded.

The method can include determining a mass flow rate W of working fluid circulating through the compressor stage, determining a control parameter value associated to the geometrical configuration of the variable geometry element based on the determined value of mass flow rate W; and changing the geometrical configuration of the variable geometry element in accordance with the determined control parameter value.

A combustion engine including at least one combustion chamber, a first bleed air supply fluidly coupled to a portion of the combustion engine upstream the combustion chamber, a second bleed air supply fluidly coupled to a portion of the combustion engine downstream the combustion chamber, a first thermal bus, and a turbomachine including a compressor, a rotary pump, and a first turbine, with the compressor and rotary pump in serial flow arrangement and the rotary pump being fluidly coupled to the first thermal bus.