A centrifugal compressor for a chiller system includes a casing having an inlet portion and an outlet portion, a recirculation structure including a recirculation path and a recirculation discharge cavity, an impeller disposed downstream of the recirculation discharge cavity, the impeller being attached to a shaft rotatable about a shaft rotation axis, a motor arranged to rotate the shaft in order to rotate the impeller, and a diffuser disposed in the outlet portion downstream of the impeller. The recirculation structure is configured and arranged to impart a swirl to a flow of refrigerant into the inlet portion, with a velocity of a recirculation flow caused by the swirl being higher than a velocity of the flow of the refrigerant in the inlet portion.

An example centrifugal compressor includes a housing that defines an inlet chamber and includes first and second openings that define a recirculation passage in fluid communication with the inlet chamber. An impeller is disposed within the housing and is rotatable about a longitudinal axis to draw fluid into the inlet chamber. The first and second openings are at different axial locations along the longitudinal axis. A plurality of inlet guide vanes are rotatable and situated in the inlet chamber. The centrifugal compressor includes a ring and a controller for moving the ring along the longitudinal axis between a first position and a second position when rotating the inlet guide vanes. The ring obstructs at least one of the first and second openings more in the second position than in the first position.

A technique for controlling a rotating stall in a compressor of a gas turbine engine. In the technique a flow injection is introduced into an axial air flow path of the compressor via a flow-injection opening located at a pressure side of a guide vane in the compressor and directed towards a leading edge of a compressor rotor blade located adjacently downstream of the guide vane. The flow injection is introduced when the rotating stall is detected and/or when the compressor is being operated at a speed lower than full load speed. The flow injection reduces an angle of incidence of compressor air on the leading edge of the downstream rotor blade and hence the rotor sees a more favorable velocity. The favorable velocity results into an increase in the operating range of the rotor and hence of the compressor by mitigating and/or reducing the rotating stalls.

A bleed valve system comprises a duct, featuring a central longitudinal axis and allowing a main flow of fluid to pass from a first environment at a first static pressure to a second environment at a second static pressure along a bleed direction, a valve comprising a valve member arranged within the duct between the first and second environments and movable to partially obstruct the duct and deviate the main flow of fluid to direct at least a part of it towards a portion of an internal wall of the duct; and an ejector, arranged within the duct, downstream of the valve member and offset from the central longitudinal axis in correspondence of said portion of the internal wall, adapted to supply an additional flow of fluid within the duct to accelerate the main flow of fluid and reduce the second static pressure.

An internal combustion engine having a turbocharger with variability at the compressor inlet, and a turbocharger. An internal combustion engine having a turbocharger, and a turbocharger, are described. A device which both performs a change in the cross section of the compressor inlet and brings about an adjustment of the exhaust gas recirculation rate is arranged in the region of the compressor inlet. As a result, the turbocharger is of space-saving and low-cost construction in the compressor inlet region.

A system for delivering a flow stream of a gas to a compressor. A shroud extends from an inlet to the compressor and defines a main inlet passage configured to direct the flow stream from the inlet to the compressor. A communication plenum is separated from the main inlet passage. A port system includes first and second port subsystems that each provide an opening between the main inlet passage and the communication plenum. The first port subsystem is disposed further from the compressor than the second port subsystem. The port system is configured so that a portion of the gas enters or exits the compressor through the second port subsystem, depending on operating conditions of the compressor.

An apparatus for diagnosing and controlling the aerodynamic stability of a compressor and method there of are provided. The apparatus includes a measurement device (100), a signal processing device (200) and a control and execution device (300), wherein the measurement device (100) is configured to measure the pressure or velocity fluctuations of air flows in different positions inside a compressor in real time, and to transmit real-time measurement signals obtained from different positions to the signal processing device (200); the signal processing device (200) is configured to determine, according to the real-time measurement signals, a type and spatial distribution of instability precursor in the compressor, and to output corresponding control strategy signals to the control and execution device (300); and the control and execution device (300) executes, according to the received control strategy signals, corresponding control actions to regulate the stability of the compressor (S3).

A centrifugal compressor according to an exemplary aspect of the present disclosure includes, among other things, an impeller provided in a main flow path and configured to pressurize a main flow of fluid. The compressor also includes a secondary flow path configured to provide a secondary flow by recirculating a portion of the main flow. The amount of the main flow that becomes the secondary flow is less than or equal to 15%. A method is also disclosed.

A turbocharger is provided and includes a compressor housing and a recirculation slit and a recirculation passage provided at an inlet of the compressor housing to enable air flowing into the compressor to be recirculated. A gas supply part supplies blow-by gas towards the inlet of the compressor housing to allow blow-by gas to be joined with air recirculated through the recirculation slit and the recirculation passage and to guide recirculating air towards a compressor wheel.

A compressor includes a rotor platform; a rotor blade; and a casing having an inner surface surrounding the tip and spaced radially outwardly from the tip to define a gap. A secondary air flow system includes a bleed inlet configured to remove secondary air flow from the primary air flow; an injection opening disposed in the inner surface of the casing upstream of the bleed inlet; an accessory conduit; and a plenum fluidly coupled to the bleed inlet, the injection opening, and the accessory conduit. The bleed inlet and plenum at least partially define a secondary air flow path such that a first portion of the secondary air flow is directed in through the bleed inlet, through the plenum, and out through the injection opening and a second portion of the secondary air flow is directed in through the bleed inlet, through the plenum, and out through the accessory conduit.