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.

The invention relates to a method for determining an indicator for a prediction of an instability in a compressor, which is designed as an axial or radial compressor, having the following steps: operating a compressor designed as an axial or radial compressor in operating states, which differ by different values of a characteristic parameter for a flow mass flux of the compressor, wherein the operating states are run through at decreasing flow mass fluxes; determining the values of the characteristic value for the flow mass flux for the operating states; detecting time-resolved pressure measurement values when running through the operating states by means of a pressure sensor, which is arranged in a housing of the compressor, upstream adjacent to an entrance plane of a rotor stage determining the skew for the operating states and determining an indicator for an instability of the compressor, if an algebraic sign change of the curve rise is determined for a curve profile of the skew over the characteristic parameter for the flow mass flux for the operating states. The invention further relates to the use of the method and a device for determining an indicator for a prediction of an instability in an compressor.

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.

An aircraft engine comprising a fan, the fan having a diameter D and including a plurality of fan blades, the fan blades having a sweep metric S.sub.tip, each fan blade having a leading edge, and a forward-most portion on the leading edge of each fan blade being in a first reference plane. The aircraft engine further comprises a nacelle, comprising an intake portion forward of the fan, a forward edge on the intake portion being in a second reference plane, wherein the intake portion has a length L measured along an axis of the aircraft engine between the first reference plane and the second reference plane, the aircraft engine having a cruise design point condition M.sub.rel, wherein M.sub.rel is between 0.4 and 0.93, L/D is between 0.2 and 0.45 and S.sub.tip is from −1 to 0.1.

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 present disclosure relates to a gas turbine engine for an aircraft comprising: an engine core comprising a turbine, a compressor, and a core shaft; and an environmental control system mounted on the engine core comprising a first air passage arranged to deliver air from outside the engine core to an aircraft cabin and/or for wing anti icing, a subsidiary compressor located in the first air passage and arranged to compress air in the first air passage, the subsidiary compressor being powered by the core shaft, and a second air passage arranged to inject air from the compressor into the first air passage.

The invention concerns a bypass turbomachine (1) with a primary flow path and a secondary flow path, comprising: —a low-pressure body comprising a low-pressure compressor (120) connected to a low-pressure turbine (122) via a low-pressure shaft (124), —a high-pressure body comprising a high-pressure compressor (130) connected to a high pressure turbine (132), via a high-pressure shaft (134), —a low-pressure power take-off system (220) comprising an electrical generator (226), configured to take power (W12) from the low-pressure body, wherein—the turbomachine comprises a debris removal system (500), located between the two compressors (226, 236), —the low-pressure power take-off system (220) is configured to take power (W12) from the low-pressure shaft (124) using the resistive torque of the electrical generator (226), in order to avoid a risk of surging.

A gas turbine engine includes a main compressor section having a downstream most location, and a turbine section, with both the main compressor section and the turbine section housing rotatable components. A first tap taps air compressed by the main compressor section at an upstream location upstream of the downstream most location. The first tap passes through a heat exchanger, and to a cooling compressor. Air downstream of the cooling compressor is selectively connected to reach at least one of the rotatable components. The cooling compressor is connected to rotate at a speed proportional to a rotational speed in one of the main compressor section and the turbine section. A valve system includes a check valve for selectively blocking flow downstream of the cooling compressor from reaching the at least one rotatable component. A dump valve selectively dumps air downstream of the cooling compressor. A method is also disclosed.

Methods, apparatus, systems, and articles of manufacture are disclosed to detect air flow separation of an engine. An example apparatus includes hardware, and memory including instructions that, when executed, cause the hardware to at least determine an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of a turbofan and a second pressure value from a second pressure sensor included in the nacelle, determine a severity level parameter based on the inlet flow separation parameter, the severity level parameter based on a difference between the first pressure value and the second pressure value, and adjust a contribution of airflow from aft of a fan of the turbofan based on the severity level parameter.

A fan case assembly adapted for use with a gas turbine engine includes a fan track liner and an annular case. The fan track liner extends circumferentially at least partway about a central axis of the gas turbine engine. The annular case is configured to support the fan track liner at a radial position relative to the central axis. The fan case assembly further includes an air recirculation duct configured to redirect air around the fan track liner.