Abstract: There is disclosed a fan assembly including a fan rotor including a hub and fan blades. The fan blades have a leading edge and a trailing edge. A fan stator downstream of the fan rotor relative to a direction of an airflow through the fan assembly. The fan stator includes vanes extending between radially inner ends and radially outer ends. A flow recirculation circuit has an inlet downstream of radially inner ends of the vanes of the fan stator and an outlet upstream of radially inner ends of the vanes. A recirculation stator has a plurality of stationary guide vanes circumferentially distributed around the axis and located in the flow recirculation circuit between the inlet and the outlet A method of operating the fan assembly is also disclosed.

Abstract: A compressor diffuser for a gas turbine engine includes one or more diffuser pipes having a tubular body defining an internal flow passage extending therethrough. The tubular body includes a first portion extending in a first direction, a second portion extending in a second direction different from the first direction, and a curved portion fluidly linking the first portion and the second portion. A splitter vane is disposed within the internal flow passage of the curved portion of the tubular body, the splitter vane defining a convergent flow passage between itself and a radially inner wall of the curved portion, and a divergent flow passage between itself and a radially outer wall of the curved portion.

Abstract: A compressor of a gas turbine engine includes a rotor and a stator located downstream of the rotor. The stator has a plurality of vanes each with an airfoil extending span-wise between a root proximate an inner hub of the stator and a tip. A fillet is disposed at the leading edge of the root of the airfoil, and extends between a pressure side surface of the airfoil and the inner hub.

Abstract: A fan assembly for a gas turbine engine includes a fan rotor having a hub and fan blades protruding from the hub. A fan stator is located downstream of the fan rotor and has vanes extending between radially inner ends and radially outer ends. A flow recirculation circuit has an inlet located downstream of the vanes of the fan stator and adjacent the radially inner ends thereof. The flow recirculation circuit has an outlet located upstream of the inlet. The outlet is located at the hub of the fan rotor and upstream of trailing edges of the fan blades.

Abstract: A compressor diffuser for a gas turbine engine includes one or more diffuser pipes having a tubular body defining an internal flow passage extending therethrough. The tubular body includes a first portion extending in a first direction, a second portion extending in a second direction different from the first direction, and a curved portion fluidly linking the first portion and the second portion. A splitter vane is disposed within the internal flow passage of the curved portion of the tubular body, the splitter vane defining a convergent flow passage between itself and a radially inner wall of the curved portion.

Abstract: A diffuser for a centrifugal compressor includes a diffuser pipe having an internal flow passage extending therethrough between an inlet and an outlet, a bend in the internal flow passage disposed between the inlet and the outlet, and a throat defined in the internal flow passage downstream of the inlet and upstream of the bend. One or more vortex generators project into the internal flow passage, and the vortex generators are disposed downstream of the throat and upstream of the bend. A method for diffusing fluid flow in a diffuser of a compressor is also described. In operation, the vortex generators engage fluid flow in the internal flow passage to generate downstream vortices.

Abstract: A rotor casing having an inner casing wall surrounding an annular gas path, a plurality of rotor blades radially extending into such annular gas path. The inner casing wall has an annular recess positioned radially outwardly of the gas path outer line and axially downstream of the rotor blades. A plurality of circumferentially spaced-apart vanes are positioned within the annular recess. The vanes may be profiled and circumferentially spaced from one another to accelerate air flowing between circumferentially adjacent vanes. The vanes may include an airflow partition extending between the top edges of at least 2 circumferentially adjacent vanes, from each such vanes' leading edge to each such vanes' trailing edge.

Abstract: A rotor casing having an inner casing wall surrounding an annular gas path, a plurality of rotor blades radially extending into such annular gas path. The inner casing wall has an annular recess positioned radially outwardly of the gas path outer line and axially downstream of the rotor blades. A plurality of circumferentially spaced-apart vanes are positioned within the annular recess. The vanes may be profiled and circumferentially spaced from one another to accelerate air flowing between circumferentially adjacent vanes. The vanes may include an airflow partition extending between the top edges of at least 2 circumferentially adjacent vanes, from each such vanes' leading edge to each such vanes' trailing edge.

Abstract: A diffuser for a centrifugal compressor includes a diffuser pipe having an internal flow passage extending therethrough between an inlet and an outlet, a bend in the internal flow passage disposed between the inlet and the outlet, and a throat defined in the internal flow passage downstream of the inlet and upstream of the bend. One or more vortex generators project into the internal flow passage, and the vortex generators are disposed downstream of the throat and upstream of the bend. A method for diffusing fluid flow in a diffuser of a compressor is also described. In operation, the vortex generators engage fluid flow in the internal flow passage to generate downstream vortices.

Abstract: A gas turbine engine that comprises an engine core having a compressor, a turbine, a combustor, and a rotation axis. The engine further comprising a fan case wall having a radially-inner surface, a by-pass duct between the fan case wall and around the engine core, a plurality of struts circumferentially distributed and extending across the by-pass duct, a surface cooler adjacent to the radially-inner surface of the fan case and configured to be exposed to a by-pass air flow through the by-pass duct during operation of the gas turbine engine, the surface cooler fluidly communicating with a fluid circuit of the engine requiring cooling for of a fluid, and a recirculation conduit extending between an inlet in the radially-inner surface of the fan case disposed downstream of the surface cooler and an outlet in the radially-inner surface of the fan case wall disposed upstream of the surface cooler.

Abstract: A vane diffuser for diffusing gases is disclosed. The diffuser has an annular diffuser body including a plurality of diffuser vanes defining diffuser passages. The diffuser passages are circumferentially distributed. A direction of main gas flow through the diffuser passages is defined from a passage inlet in fluid communication with the outlet of the compressor to a passage outlet. A plurality of fluid injection conduits each extend between a conduit inlet and a conduit outlet for at least one of the diffuser vanes. The conduit outlet defines at least one opening in at least one of the pressure and suction side surfaces and is configured to inject fluid along one of the pressure and suction side surfaces in the direction of main gas flow through the corresponding diffuser passage.

Abstract: A compressor diffuser for a gas turbine engine which includes at least one diffuser pipe having a tubular body with an inner surface defining an internal flow passage extending therethrough. The tubular body includes a first portion that extends in a first direction and defines a throat therein, a second portion that extends in a second direction different from the first direction, and a curved portion fluidly linking the first portion and the second portion. A plurality of vortex generators are disposed within the diffuser pipe and extend from the inner surface into the internal flow passage. The vortex generators are disposed downstream of the throat in the first portion of the diffuser pipe and upstream of the curved portion. In operation, the vortex generators engage fluid flow in the internal flow passage to generate downstream vortices.

Abstract: A gas turbine engine compressor includes a rotor defining a central axis of rotation and a plurality of blades which project into an annular compressor gas flow passage, and a shroud circumferentially surrounding the rotor and having a radially inner surface adjacent to the blade tips. Bleed holes extend through the shroud adjacent the blade tips, each of the bleed holes having an inlet end disposed in the shroud radially inner surface and an outlet end disposed in a shroud radially outer surface. Bleed air removed from the annular gas flow passage flows through the bleed holes from the inlet to the outlet ends. The outlet end of each bleed hole is located circumferentially upstream of the inlet end relative to a direction of rotational flow in the annular gas flow passage driven by a direction of rotation of the rotor.

Abstract: A centrifugal compressor having at least a diffuser is disclosed. The diffuser has an annular diffuser body having circumferentially spaced apart diffuser passages defining fluid paths through the diffuser body. The diffuser also has a plurality of diffusion members mounted to the annular diffuser body. Each diffusion member has a member inlet in fluid communication with a diffuser passage and a member outlet. Each diffusion member defines an aerodynamic throat disposed between the member inlet and the member outlet. The diffuser also has a fluid injection assembly with multiple injection conduits. Each injection conduit extends between a conduit inlet configured to receive a flow of compressible fluid from a supply and a conduit outlet communicating with a corresponding diffusion member downstream of the aerodynamic throat. The compressible fluid is injected through the conduit outlet into the diffusion members.

Abstract: A compressor for a gas turbine engine having a bleed air recirculation system includes a plurality of bleed holes extending through the shroud at a first axial location thereon substantially adjacent the blade tips. The bleed holes have a closed outer perimeter along their complete length. An annular bleed cavity surrounds the shroud and is in communication with outlet openings of the bleed holes. The bleed holes provide communication between the main gas flow passage and the bleed cavity. The bleed cavity includes exit passages having outlets disposed in the shroud at a second axial location which is upstream of both the first axial location and the leading edge of the blades of the rotor. Bleed air is passively bled from the main gas flow passage via the bleed holes, recirculated through the bleed cavity and re-injected back into the main gas flow passage at the second axial location.

Abstract: The centrifugal compressor described includes an impeller shroud which encloses the impeller and has a curved shroud surface that extends between an inducer portion and an exducer portion. The compressor includes one or more circumferential grooves in the shroud body within the exducer portion. Each groove has opposed wall segments spaced apart therefrom. The wall segments are inclined at a nonzero groove angle relative to a normal of the shroud surface in a direction opposite the fluid flow path along the shroud surface.

Abstract: A compressor diffuser for a gas turbine engine which includes at least one diffuser pipe having a tubular body with an inner surface defining an internal flow passage extending therethrough. The tubular body includes a first portion that extends in a first direction and defines a throat therein, a second portion that extends in a second direction different from the first direction, and a curved portion fluidly linking the first portion and the second portion. A plurality of vortex generators are disposed within the diffuser pipe and extend from the inner surface into the internal flow passage. The vortex generators are disposed downstream of the throat in the first portion of the diffuser pipe and upstream of the curved portion. In operation, the vortex generators engage fluid flow in the internal flow passage to generate downstream vortices.

Abstract: A gas turbine engine includes rotor having a hub, and a plurality of blades extending generally radially from the hub. Each of the blades has an airfoil portion. The airfoil portion has a leading edge and a trailing edge defining a chordwise direction, and a root and a tip defining a spanwise direction. Only a sub-set of the blades has a cutback at at least one of the trailing edge and the leading edge. A method of designing and a method of assembling a rotor having noise reduction properties in a gas turbine engine is also presented.

Abstract: A compressor diffuser for a gas turbine engine includes a plurality of diffuser pipes each having a diverging tubular body defining a flow passage extending fully therethrough. The tubular body includes a first portion extending in a first direction, a second portion extending in a second direction different from the first direction, and a curved portion interconnecting the first portion and the second portion. At least one splitter vane extends into the flow passage and disposed at least partially within the curved portion of the tubular body.

Abstract: A centrifugal compressor having at least a diffuser is disclosed. The diffuser has an annular diffuser body having circumferentially spaced apart diffuser passages defining fluid paths through the diffuser body. The diffuser also has a plurality of diffusion members mounted to the annular diffuser body. Each diffusion member has a member inlet in fluid communication with a diffuser passage and a member outlet. Each diffusion member defines an aerodynamic throat disposed between the member inlet and the member outlet. The diffuser also has a fluid injection assembly with multiple injection conduits. Each injection conduit extends between a conduit inlet configured to receive a flow of compressible fluid from a supply and a conduit outlet communicating with a corresponding diffusion member downstream of the aerodynamic throat. The compressible fluid is injected through the conduit outlet into the diffusion members.