Abstract: A gas turbine engine includes first and second stages having a rotational axis. A mid turbine frame is arranged axially between the first and second stages. The mid turbine frame includes a circumferential array of airfoils, and the airfoils each have a curvature provided equidistantly between pressure and suction sides. The airfoils extend from a leading edge to a trailing edge at a midspan plane along the airfoil. An angle is defined between first and second lines respectively tangent to the intersection of the plane and the curvature at airfoil leading and trailing edges. The angle is equal to or greater than about 10°, for example. In one example, an airfoil aspect ratio is less than 1.5.

Abstract: A turbofan engine has an engine case and a gaspath through the engine case. A fan has a circumferential array of fan blades. The engine further has a compressor, a combustor, a gas generating turbine, and a low pressure turbine section. A speed reduction mechanism couples the low pressure turbine section to the fan. A bypass area ratio is greater than about 6.0. The low pressure turbine section airfoil count to bypass area ratio is below about 170.

Abstract: A low pressure turbine for a gas turbine engine includes inner and outer counter-rotating rotor sets, with both said rotor sets driving a common shaft.

Abstract: An impeller includes a plurality of vanes formed around a hub, each of the plurality of vanes defines an offset between a leading edge and a trailing edge.

Abstract: An example airfoil array includes an airfoil array configured to rotate within a turbomachine at a different rotational speed than a fan within the turbomachine. The airfoil array includes a first airfoil that is circumferentially spaced a distance from an adjacent second airfoil. A ratio of the distance to an axial chord length of the first airfoil is less than 1.3. An uncovered turning angle of the first airfoil is greater than 15 degrees.

Abstract: A turbine section of a gas turbine engine includes an arcuate vane platform segment having a substantially flat surface over which a rotational turbine vane may swing.

Abstract: An airfoil with turning flow comprises a first surface, a second surface, a leading edge and a trailing edge. The first and second surfaces extend from the leading edge to a trailing edge. A chord extends from a midpoint of the leading edge to a midpoint of the trailing edge, defining a duct angle of at least fifteen degrees with respect to a turbine axis. An axial length of the chord defines an aspect ratio of at most one with respect to an average radial span of the leading and trailing edges. In a region of the trailing edge, an axial angle is at most four degrees and a circumferential angle is at most ten degrees, where the circumferential angle is defined in a direction opposite the turning flow.

Abstract: Gas turbine engine systems involving mechanically alterable vane throat areas are provided. In this regard, a representative vane for a gas turbine engine includes: a leading edge; a trailing edge; a suction side surface extending between the leading edge and the trailing edge; a cavity having an aperture located in the suction side surface; and a barrel located within the cavity and being moveable therein such that movement of the barrel alters an extent to which the barrel protrudes through the aperture.

Abstract: An airfoil with turning flow comprises a first surface, a second surface, a leading edge and a trailing edge. The first and second surfaces extend from the leading edge to a trailing edge. A chord extends from a midpoint of the leading edge to a midpoint of the trailing edge, defining a duct angle of at least fifteen degrees with respect to a turbine axis. An axial length of the chord defines an aspect ratio of at most one with respect to an average radial span of the leading and trailing edges. In a region of the trailing edge, an axial angle is at most four degrees and a circumferential angle is at most ten degrees, where the circumferential angle is defined in a direction opposite the turning flow.

Abstract: A low pressure turbine for a gas turbine engine includes inner and outer counter-rotating rotor sets, with both said rotor sets driving a common shaft.

Abstract: A turbine section of a gas turbine engine includes an arcuate vane platform segment having a substantially flat surface over which a rotational turbine vane may swing.

Abstract: Gas turbine engine systems involving mechanically alterable vane throat areas are provided. In this regard, a representative vane for a gas turbine engine includes: a leading edge; a trailing edge; a suction side surface extending between the leading edge and the trailing edge; a cavity having an aperture located in the suction side surface; and a barrel located within the cavity and being moveable therein such that movement of the barrel alters an extent to which the barrel protrudes through the aperture.

Abstract: Provided is an aerodynamic profile for use in gas turbine airfoil and a turbine blade comprising such profiles. The profiles counteract a reduction in area between adjacent airfoils due to an increase in coating thickness. A plurality of radial sections forms both coated and uncoated nominal profiles of the airfoils. The sections are located within a tolerance measured in any direction perpendicular to an airfoil stacking line extending radially from a central axis and defined by X, Y, and R Cartesian coordinate values in inches. The R values are measured perpendicular to a plane normal to the airfoil stacking line with R values of zero at a lowermost radial section and increasing in the radial direction. The X and Y values are measured perpendicular to the airfoil stacking line.

Abstract: An improvement for extending the stable operating range of a centrifugal compressor comprises a circumferentially extending series of slots adjacent the leading edges of a series of compressor vanes such that there is relative motion between the series of slots and the vanes as the compressor impeller is driven in rotation.