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 gas turbine engine compressor has an annular gas path, a circumferential array of variable inlet guide vanes (VIGVs), pivotally mounted and positioned within the annular gas path; and a rotor positioned adjacently downstream of the array of variable inlet guide vanes. The rotor has a platform extension extending upstream towards the inlet guide vanes. The platform extension axially overlaps an inner end surface of the variable inlet guide vanes.

Abstract: A compressor of a gas turbine engine is described which includes a rotor and a stator located immediately downstream of the rotor. The stator comprises a plurality of stator vanes each having an airfoil extending along a generally radial span between a root and a tip of the airfoil. The radially inner portion has aerodynamic forward sweep at the leading edge, the forward sweep having a maximum forward sweep that is more forward than a sweep at the leading edge in the intermediate portion.

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: An airfoil for a gas turbine engine comprises at least three successive sections defined between a root and a tip. A first decrease of maximum thickness-to-chord ratios defined by a difference between a maximum thickness-to-chord ratio at the root and a maximum thickness-to-chord ratio at a first spanwise position, a second decrease of the maximum thickness-to-chord ratios defined by a difference between the maximum thickness-to-chord ratio at the first spanwise position and a maximum thickness-to-chord ratio at a second spanwise position, a third decrease of the maximum thickness-to-chord ratios defined by a difference between the maximum thickness-to-chord ratio at the second spanwise position and a maximum thickness-to-chord ratio at the tip, the second decrease being greater than the corresponding first and third decreases.

Abstract: Assemblies and methods for providing injection air to influence flow in a flow passage defined by a fan of a gas turbine engine are disclosed. In one embodiment, the method comprises: receiving air into an interior of a nose cone; increasing the pressure of the air in the interior of the nose cone and directing the pressurized air; and discharging the air into the flow passage defined by the fan.

Abstract: A compressor rotor airfoil in a gas turbine engine is presented. Opposed pressure and suction sides are joined together at chordally opposite leading and trailing edges. The pressure and suction sides extend in a span direction from a root to a tip. A leading edge dihedral angle is defined at a point on the leading edge between a tangent to the airfoil and a vertical. The leading edge dihedral angle has a span-wise distribution. The distribution has at least one inflection point. A method of reducing a rub angle between a compressor rotor blade and a casing surrounding the blade is also presented.

Abstract: An airfoil in a gas turbine engine includes opposed pressure and suction sides joined together at chordally opposite leading and trailing edges. The pressure and suction sides extend spanwise from a root to a tip of the airfoil. The airfoil has a spanwise distribution of maximum thicknesses of chordwise cross-sections of the airfoil. The spanwise distribution of maximum thicknesses decreases from the root to the tip. In one aspect, the spanwise distribution is stepped between a first portion extending from the root and a second portion extending to the tip.

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 rotor airfoil in a gas turbine engine is presented. Opposed pressure and suction sides are joined together at chordally opposite leading and trailing edges. The pressure and suction sides extend in a span direction from a root to a tip. A leading edge dihedral angle is defined at a point on the leading edge between a tangent to the airfoil and a vertical. The leading edge dihedral angle has a span-wise distribution. The distribution has at least one inflection point. A method of reducing a rub angle between a compressor rotor blade and a casing surrounding the blade is also presented.

Abstract: A compressor airfoil in a gas turbine engine is presented. Opposed pressure and suction sides are joined together at chordally opposite leading and trailing edges. The pressure and suction sides extend in a span direction from a root to a tip of the airfoil. A leading edge sweep angle is defined relative to a tangent to the airfoil and flow velocity vector at a point on the leading edge. A leading edge dihedral angle is defined relative to the tangent to the airfoil and a vertical at the point on the leading edge. A ratio of the leading edge sweep angle to the leading edge dihedral angle being smaller than 1. A method of forming such airfoil is also presented.

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 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: An impeller for increasing the pressure of a fluid circulating in an annular fluid path, the impeller comprising: a plurality of centrifugal compressor vanes circumferentially interspaced around the axis of the annular fluid path, the plurality of compressor vanes extending from an axially-oriented inlet to a radially-oriented outlet, and each having an inner edge and a free edge, the free edge of the plurality of compressor vanes coinciding with an outer limit of the annular fluid path, and a hub having a solid-of-revolution shape centered around an axis, the hub having an outer hub surface forming an inner limit to the annular fluid path and to which the inner edge of the plurality of centrifugal vanes is secured, the outer hub surface having a portion which leans forward, forming an axial recess therein.

Abstract: An airfoil in a gas turbine engine includes opposed pressure and suction sides joined together at chordally opposite leading and trailing edges. The pressure and suction sides extend spanwise from a root to a tip of the airfoil. The airfoil has a spanwise distribution of maximum thicknesses of chordwise cross-sections of the airfoil. The spanwise distribution of maximum thicknesses decreases from the root to the tip. In one aspect, the spanwise distribution is stepped between a first portion extending from the root and a second portion extending to the tip.

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 rotary airfoil in a gas turbine engine is provided. The airfoil includes opposed pressure and suction sides joined together at chordally opposite leading and trailing edges. The pressure and suction sides extend in a span direction from a root to a tip. An axial component of a center of gravity of a cross-section taken chordally toward the tip of the airfoil being upstream relative to an axial component of a center of gravity of a cross-section taken chordally toward the root of the airfoil. A method for forming such blade is also presented.