A centrifugal compressor diffuser (42) includes a plurality of diffuser flow passages (22) extending through an annular diffuser housing (20) and circumferentially bounded by diffuser vanes (23) and axially bounded by forward and aft walls (101, 100). A diffuser boundary layer bleed (96) for the passages may include boundary layer bleed apertures (106) or slots (130) disposed through the forward wall (101) and a downstream facing wall (142) canted at an acute cant angle to a downstream diffuser airflow direction (103) in the passages. Diffuser bleed flow (112) is bled from a diffuser boundary layer. Boundary layer bleed apertures can be located downstream of throat sections (28) of the flow passages near pressure sides of the vanes. A centrifugal compressor (18) may include the diffuser surrounding an annular centrifugal compressor impeller (32) and apparatus for flowing impeller bleed flow (102) from a radial clearance between an impeller tip (36) and a diffuser annular inlet (27) with diffuser bleed flow either mixed or separately to cool a turbine (16).

The invention relates to a method for determining the pressure P.sub.avcm upstream of a mechanical compressor (3) equipped with a double supercharging circuit of a combustion engine. The pressure P.sub.avcm is determined by a dynamic model based on a law of conservation of flow rate in the volume upstream of the mechanical compressor. The model links the pressure P.sub.avcm upstream of the mechanical compressor (3) to a temperature T.sub.avcm upstream of the mechanical compressor (3), to a boost pressure P.sub.sural and boost temperature T.sub.sural on the intake side of the engine, and to an openness Bypass of the bypass valve (4).

A diagonal fan having an electric motor, a housing and a diagonal impeller generating a diagonal flow which is deflected into an axial flow direction. The diagonal impeller has impeller blades, an air inlet and an air outlet, wherein the housing forms a flow channel for an airflow generated by the diagonal impeller, which has a non-rotationally symmetric axial section and a cylindrical axial section axially directly adjacent, as seen in the flow direction, wherein an air outlet-side radial outer end of the diagonal impeller is arranged in the cylindrical axial section of the flow channel of the housing and an air gap is provided between the radial outer end and the housing, and wherein the non-rotationally symmetric axial section of the flow channel is arranged in a region of the flow channel which is adjacent to the air-inlet side of the air gap in an axial plane with the diagonal impeller.

An electrically driven pump for gases or gas mixtures having a pump housing and a motor housing. A radial pump having a pump impeller is formed in the pump housing, and the pump impeller is connected to a drive shaft which extends through a wall of the pump housing into the motor housing. At least one air gap is formed between the drive shaft and the wall of the pump housing. A pressure side is formed in the pump housing, and is arranged in the outer radial region of the pump impeller. An opening through the pump housing is formed in the region of the pressure side, and the opening connects the interior of the pump housing to the interior of the motor housing, such that the pressure prevailing on the pressure side may propagate into the interior of the motor housing.

A system has an electric motor having a stator and a rotor. The rotor rotates with a shaft and the shaft drives a fluid rotor. A control senses a fault condition on the electric motor. The control actuates a speed reduction feature when a fault is detected to bring rotation of the motor rotor and the fluid rotor to a stop more rapidly than if the speed reduction feature had not been actuated.

A fuel pump system for a turbomachine engine can include a boost pump driven by an electric motor and configured to be in fluid communication with a fuel tank, a primary pump configured to be driven by a shaft connected to the turbomachine engine, wherein the primary pump is in fluid communication with the boost pump downstream of the boost pump by a boost branch, a bypass flow branch that connects the boost branch to a downstream branch that is downstream of the primary pump, the downstream branch is in fluid communication with one or more metering valves and/or one or more fuel nozzles, and a bypass valve disposed in the bypass flow branch and/or the downstream branch and configured to selectively directly fluidly communicate the boost branch and the downstream branch.

The centrifugal compressor (1) includes: an impeller (3); and a casing (2) accommodating the impeller (3). The casing (2) includes: an inlet (6); an impeller-accommodating portion (14) in which the impeller (3) is disposed; an annular chamber (11) formed around the inlet (6); a downstream groove (13) communicating a downstream end portion of the annular chamber (11) with the impeller-accommodating portion (14); and an upstream groove (12) communicating an upstream end portion of the annular chamber (11) with the inlet (6). In addition, the downstream groove (13) is provided in a predetermined range in a circumferential direction of the impeller (3) so as to communicate with a high-pressure part to occur in part of the impeller-accommodating portion (14), and the upstream groove (12) is provided over the entire circumference of the inlet (6).

An engine bleed air system of an aircraft, comprising a heat exchanger which comprises a rectangular core with a rectangular outlet section, a cylindrical outlet duct and a transition area between the rectangular outlet section of the rectangular core and the cylindrical outlet duct, and at least a downstream system, further comprising a flow deflector located at least in the cylindrical outlet duct, such that the outlet flow characteristics homogeneity are improved and a particular flow deflection and distribution of the outlet flow is achieved, avoiding the damage of the at least one downstream system. The invention also provides a method for homogenizing the temperature of the outlet flow of a heat exchanger outlet in an engine bleed air system of an aircraft.

A gas turbine engine comprises an engine having a compressor section, and a turbine section. A firewall and accessory pumps are mounted on a downstream side of the firewall. The accessory pumps are driven by electric motors mounted on the firewall on an upstream side of the firewall.

A reverse flow gas turbine engine has a low pressure (LP) spool and a high pressure (HP) spool arranged sequentially in an axial direction. The LP spool comprises an LP compressor disposed forward of an LP turbine and drivingly connected thereto via an LP compressor gear train. The HP spool comprises an HP compressor in flow communication with the LP compressor, and an HP turbine disposed forward of the HP compressor and drivingly connected thereto via an HP shaft.