A compressor includes a compressor screen mounted on the outer circumferential surface of a compressor disk or the inner wall of a compressor casing. The compressor screen is positioned between a row of compressor blades and a row of compressor vanes to stabilize airflow by regulating the amount of air flowing in the compressor. The compressor screen is formed of annular plate having openings through which the compressed air flows, arranged in a pattern to smoothly regulate the flow of air. The compressor screen may be variously configured, for example, to facilitate installation or to guide the flow of air using a tapered surface or a directionality of the openings or a flow guide. A gas turbine includes a combustor, a turbine, and a compressor employing the compressor screen.

A system for measuring turbulence of a flow of a turbine engine, notably of a turbine engine compressor includes a first housing with a first pressure sensor and a first inlet, a second housing with a second pressure sensor and a second inlet inclined relative to the first inlet, and a temperature sensor. The system is configured to calculate at least two orientation components of the velocity of the flow on the basis of the pressure sensors and the temperature sensor. The inlets are disposed at the vane foot, on the leading edge at the level of an internal shell.

A system and method for detecting inlet temperature distortion of an engine are described. The method comprises obtaining an outside air temperature from at least one first sensor, obtaining an inlet temperature of the engine from at least one second sensor, determining an inlet temperature distortion based on a difference between the outside air temperature and the inlet temperature, comparing the inlet temperature distortion to a threshold, and issuing an alert when the inlet temperature distortion exceeds the threshold.

A method for actively damping oscillations in a compression process, the method being performed by a controller. The method includes acquiring process data from a compression process, performing oscillation frequency estimation of any detected oscillations in the process data, generating a damping signal based on the oscillation frequency estimation, and providing the damping signal to an electrical drive of the compression process.

A gas turbine engine includes a fan section that has a fan. A fan casing surrounds the fan section. A compressor section defines an engine axis. A gear train reduces a rotational speed of the fan relative to a shaft. A low pressure turbine is coupled to the shaft. A nacelle extends along the engine axis and surrounds the fan casing, a bypass ratio of greater than 10. A variable area fan nozzle defines a discharge airflow area. A flutter sensing system includes a controller programmed to move the variable area fan nozzle to vary the discharge airflow area in response to detecting an airfoil flutter condition associated with adjacent airfoils of the fan.

A method of operation for a gas turbine engine according to an exemplary aspect of the present disclosure includes, among other things, reducing a rotational speed of a fan relative to a shaft through a gear train, driving the shaft with a first turbine, driving a compressor with a second turbine, communicating airflow from the fan through a bypass passage defined by a nacelle, the nacelle extending along an engine axis and surrounding the fan, and having a bypass ratio of greater than 10, discharging the airflow through a variable area fan nozzle defining a discharge airflow area, detecting an airfoil flutter condition associated with adjacent airfoils of the fan, and moving the variable area fan nozzle to vary the discharge airflow area and mitigate the airfoil flutter condition.

A bleed air valve comprises a piston that moves along a guide, where the piston includes a first surface and an opposing second surface. A pressure divider network includes a divider network inlet having an inlet cross sectional area in fluid communication with a fluid passage, a divider network outlet having an outlet cross sectional area in fluid communication with ambient pressure, and a network chamber in fluid communication with the divider network inlet and the divider network outlet. The network chamber has a pressure value between pressure at the divider network inlet and pressure at the divider network outlet. A shuttle valve includes a shuttle inlet and a shuttle outlet, where the shuttle outlet is in fluid communication with the first surface. An electromechanical valve receives a command signal and in response provides compressed air to an electromechanical valve output that is in fluid communication with the shuttle inlet.

A low pressure compressor section of a gas turbine engine includes low pressure compressor stages spaced apart along an axis of rotation of the low pressure compressor section. The low pressure compressor section includes at least one of a fluid conduit extending between an air inlet of the gas turbine engine and the low pressure compression stages. The fluid conduit having at least one flow diverter displaceable between a first position and a second position to modulate air through the low pressure compressor stages. And/or a compressor stage disabler is engageable with at least one of the low pressure compressor stages and configured to reduce a rotation thereof.

A bleed air valve comprises a piston that moves along a guide, where the piston includes a first surface and an opposing second surface. A pressure divider network includes a divider network inlet having an inlet cross sectional area in fluid communication with a fluid passage, a divider network outlet having an outlet cross sectional area in fluid communication with ambient pressure, and a network chamber in fluid communication with the divider network inlet and the divider network outlet. The network chamber has a pressure value between pressure at the divider network inlet and pressure at the divider network outlet. A shuttle valve includes a shuttle inlet and a shuttle outlet, where the shuttle outlet is in fluid communication with the first surface. An electromechanical valve receives a command signal and in response provides compressed air to an electromechanical valve output that is in fluid communication with the shuttle inlet.

A bleed valve includes a housing with an inlet coupled to an outlet by a duct, a guide tube with an orifice fixed in the housing between the inlet and the outlet, a piston, and baffle. The piston is slideably supported on the guide tube and is movable between an open and a closed position, the duct fluidly coupling the inlet and outlet in the open position, the duct fluidly separating the inlet and outlet in the closed position. The orifice fluidly couples the inlet and outlet in the open and closed positions to move piston between the open and closed positions according to differential pressure between the bleed valve inlet and outlet. The baffle is slideably supported by the guide tube to set the differential pressure at which the piston moves between the open and closed positions. Gas turbines and differential pressure adjustment methods are also described.