A bleed valve includes a housing with an inlet coupled to an outlet by a duct. A guide tube is fixed within the housing between the inlet and the outlet. A piston with a piston orifice is slideably supported on the guide tube and movable between an open position and a closed position. The duct fluidly couples the inlet to the outlet in the open position, the duct fluidly separates the inlet from the outlet in the closed position, and the piston orifice fluidly couples the inlet with the outlet in the open position and the closed position to move piston between the open position and the closed position according to differential in pressure between the inlet and the outlet of the bleed valve. Compressors, gas turbine engines, and methods of controlling fluid flow are also described.

A gas turbine engine includes a fan section that has a fan with a plurality of airfoils, a compressor section, a gear train that reduces a rotational speed of the fan relative to a shaft in operation, a turbine section that has a first turbine and a second turbine, and a bypass ratio of greater than 10. The first turbine drives the shaft. A nacelle extends along an engine axis and surrounds the fan. A variable area fan nozzle defines a discharge airflow area. A fan airfoil flutter sensing system has a first sensor that actively and selectively detects a fan airfoil flutter condition in operation, and communicates with a controller programmed to move the variable area fan nozzle and vary the discharge airflow area to mitigate the flutter condition.

A method of maintaining rotor tip clearance and compressor operational line during a transient operation of a gas turbine engine is disclosed. In various embodiments, the method includes applying high spool auxiliary power to a high speed spool for a first time period, applying low spool auxiliary power to a low speed spool for a second time period, sensing one or more operational parameters of the gas turbine engine during the transient operation, and ceasing application of power to the high speed spool, based on the one or more operational parameters.

A gas turbine engine comprising: an engine core comprising a compressor; a compressor bleed valve in communication with the compressor and configured to release bleed air from the compressor; at least one component provided at the inlet of the engine core having a de-icing conduit, configured to receive the bleed air; and a flow controller, configured to provide bleed air to the de-icing conduit of the at least one component in response to either or both of a requirement to de-ice the component and a requirement to release bleed air from the compressor to optimise operation of the core.

A centrifugal compressor includes: a housing including an intake flow path; a compressor impeller arranged in the intake flow path and including a plurality of blades; an accommodation chamber formed upstream of the blades in a flow of intake air in the housing; a movable member arranged in the accommodation chamber and movable to a protruding position where the movable member protrudes into the intake flow path and to a retracted position where the movable member is retracted from the intake flow path; a plurality of slits formed closer to the blades with respect to the accommodation chamber in the housing and connected to the intake flow path; a plurality of compartment walls circumferentially separating the plurality of slits; and an outer circumferential wall connecting radially outer ends of the plurality of compartment walls.

A turbomachine for an aircraft is provided. The turbomachine includes a plurality of radially-extending blades and an annular endwall opposite the radially-extending blades. The endwall includes an endwall treatment recessed into the endwall. The endwall treatment is characterized by a casing treatment volume compressibility factor (CTVCF), and a casing treatment normalized volume (CTNV), and a blade tip Mach number (Mtip).

Health monitoring systems and associated methods for gas turbine engines are provided. A health monitoring method includes using a microphone to acquire operation data indicative of acoustic energy generated in a core gas path of the gas turbine engine. The operation data is compared to reference data indicative of an acoustic signature of fluid noise associated with a non-normal condition in the core gas path of the gas turbine engine. Based on the comparing of the operation data to the reference data, the non-normal condition is determined to exist within the core gas path of the gas turbine engine. A signal indicative of the existence of the non-normal condition within the core gas path of the gas turbine engine is output.

During a stage (E0) of starting the turbine engine, the method of the invention comprises: an open-loop generating step (E10) of generating a fuel flow rate command (WF_OL) from at least one pre-established relationship; and a closed-loop monitoring step (E20-E30) of monitoring at least one operating parameter of the turbine engine selected from: a rate of acceleration (dN2/dt) of a compressor of the turbine engine; and a temperature (EGT) at the outlet from a turbine of the turbine engine; this monitoring step comprising maintaining (E30) the operating parameter in a determined range of values by using at least one corrector network (R1, R2, R3) associated with the parameter and suitable for delivering a signal for correcting the open-loop generated fuel flow rate command so as to maintain the operating parameter in the determined range of values.

A turbocharger for an internal combustion engine has a bearing housing, in which a rotor shaft is mounted in a rotatable manner. A compressor having a compressor wheel is arranged for conjoint rotation on the rotor shaft. A fresh air supply channel conducts a fresh air mass flow to the compressor wheel. The fresh air supply channel has a first flow cross section upstream of the compressor wheel. A flow control device is provided and is adjustable between an open position, in which the first flow cross section is opened up, and a closed position, in which the first flow cross section is reduced to a second flow cross section. The flow control device is fluidically coupled to a compressor channel of the compressor downstream of the compressor wheel, such that the flow control device is adjusted in a manner dependent on a pressure prevailing in the compressor channel.

An operating method for a gas turbine by partial-load operation, includes setting of a power setpoint value for a predefined temperature value; determining the two operating curves as a function of temperature according to the power of the gas turbine, wherein the power setpoint value is located between said operating curves; determining the difference in power of said two operating curves at the substantially constant predetermined temperature value; determining a power deviation from the predetermined power setpoint value of one of the two operating curves at the substantially constant predetermined temperature value; calculating an interpolated operating curve deviation on the basis of the difference in power and the power deviation, wherein the temperature is a turbine outlet temperature or a computationally determined turbine inlet temperature.