Abstract: A heat exchanger apparatus includes: spaced-apart peripheral walls extending between an inlet and an outlet, the peripheral walls collectively defining a flow channel which includes a diverging portion downstream of the inlet, in which a flow area is greater than a flow area at the inlet; a plurality of spaced-apart fins disposed in the flow channel, each of the fins having opposed side walls extending between an upstream leading edge and a downstream trailing edge, wherein the fins divide at least the diverging portion of the flow channel into a plurality of side-by-side flow passages; and a heat transfer structure disposed within at least one of the fins.

Abstract: A variable pitch fan for a propulsion device is provided. The variable pitch fan includes a plurality of fan blades coupled to a disk and a rotatable front hub covering the disk. Each fan blade is rotatable about a pitch axis to vary a pitch of the fan blade. The pitch is variable within a pitch range that is at least about 80° to about 130°. Each fan blade extends radially outward from the disk along a span from a root to a tip. A portion of the span adjacent the root defines a root span region, a portion of the span adjacent the tip defines a tip span region. A solidity of the variable pitch fan is at least 1.0 in the root span region.

Abstract: An unducted thrust producing system has a rotating element with an axis of rotation and a stationary element. The rotating element includes a plurality of blades, each having a blade root proximal to the axis, a blade tip remote from the axis, and a blade span measured between the blade root and the blade tip. The rotating element has a load distribution such that at any location between the blade root and 30% span the value of ?RCu in the air stream is greater than or equal to 60% of the peak ?RCu in the air stream.

Abstract: An unducted thrust producing system has a rotating element with an axis of rotation and a stationary element. The rotating element includes a plurality of blades each having a blade root proximal to the axis, a blade tip remote from the axis, and a blade span measured between the blade root and the blade tip. The rotating element has a load distribution such that at any location between the blade root and 30% span the value of ?RCu in the air stream is greater than or equal to 60% of the peak ?RCu in the air stream.

Abstract: A variable pitch fan for a propulsion device is provided. The variable pitch fan includes a plurality of fan blades coupled to a disk and a rotatable front hub covering the disk. Each fan blade is rotatable about a pitch axis to vary a pitch of the fan blade. The pitch is variable within a pitch range that is at least about 80° to about 130°. Each fan blade extends radially outward from the disk along a span from a root to a tip. A portion of the span adjacent the root defines a root span region, a portion of the span adjacent the tip defines a tip span region. A solidity of the variable pitch fan is at least 1.0 in the root span region.

Abstract: An unducted thrust producing system is provided that can include a rotating element having an axis of rotation about a central longitudinal axis and comprising a plurality of blades attached to a spinner; a stationary element positioned aft of the rotating element; and an inlet positioned between the rotating element and the stationary element such that the inlet passes radially inward of the stationary element. The rotating element defines an annular valley positioned between a first annular crown and a second annular crown, and the inlet defines an open area positioned aft of the second annular crown.

Abstract: An airfoil section of a propeller for a propulsion device includes a pressure surface and a suction surface, the pressure surface and suction surface intersecting at a leading edge and a trailing edge. The airfoil section has a meanline defined midway between the pressure surface and the suction surface and a meanline angle is defined as an angle between a tangent to the meanline and a centerline of the propeller. The blade has a meanline curvature defined as the slope of a meanline angle with respect to chord fraction along the meanline, and at least a portion of the meanline has a meanline curvature that increases from between approximately 0.1 chord fraction progressing toward the leading edge and at least a portion of the meanline has a meanline curvature that decreases from between approximately 0.1 chord fraction progressing toward the leading edge.

Abstract: An unducted thrust producing system has a rotating element with an axis of rotation and a stationary element. The rotating element includes a plurality of blades each having a blade root proximal to the axis, a blade tip remote from the axis, and a blade span measured between the blade root and the blade tip. The rotating element has a load distribution such that at any location between the blade root and 30% span the value of ?RCu in the air stream is greater than or equal to 60% of the peak ?RCu in the air stream.

Abstract: An airfoil section of a propeller for a propulsion device includes a pressure surface and a suction surface, the pressure surface and suction surface intersecting at a leading edge and a trailing edge. The airfoil section has a meanline defined midway between the pressure surface and the suction surface and a meanline angle is defined as an angle between a tangent to the meanline and a centerline of the propeller. The blade has a meanline curvature defined as the slope of a meanline angle with respect to chord fraction along the meanline, and at least a portion of the meanline has a meanline curvature that increases from between approximately 0.1 chord fraction progressing toward the leading edge and at least a portion of the meanline has a meanline curvature that decreases from between approximately 0.1 chord fraction progressing toward the leading edge.

Abstract: A turbomachine is provided having at least one row of blades oriented at a predetermined stagger. Casing grooves are provided proximate to at least a portion of the tip of the blades. The grooves are oriented substantially normal to the stagger of the blades. The normal of the blade is determined from a chord of the blade. The chord may be taken across a pair of corresponding points one the upstream and downstream end of the blade, hence across the extent of the cross-sectional shape of the blade. Alternatively, a blade chord may be determined over only a portion of the blade, for instance, from a point along the centerline of the upstream end of the blade to a second point on the centerline midway down the blade from the upstream end. Optimally, the grooves are positioned adjacent to the upstream half of the blades, but may continue across the axial extent of the blades.

Abstract: An airfoil having a root, a tip, and an outer surface for pressuring air flowable thereover. The outer surface includes one or more slots elongate in a direction selected to preclude or reduce circulation within the slots, and the one or more slots are configured to bleed a boundary layer from the outer surface to the tip utilizing one or more passageways within the airfoil.

Abstract: Disclosed is an exhaust mixer (50) including a passage (54) extending from an inlet (56) to an outlet (58) that is coincident with a centerline axis of mixer (50). Several ridges (68) are circumferentially disposed about the axis and each flare away from the centerline axis relative to a direction along the centerline axis from inlet (56) toward outlet (58). Ridges (68) each define a corresponding one of several inner channels (74) radially disposed about passage (54) that each intersect passage (54) between inlet (56) and outlet (58). Several outer channels (84) are also radially disposed about passage (54) and are each positioned between a corresponding pair of inner channels (74). Ridges are each shaped to turn inner channels (74 and outer channels (84) about the axis as ridges (68) extend along the indicated direction. Inner channels (74) diverge away from the axis and one another in this direction while outer channels (84) converge toward the axis and one another in this direction.

Abstract: Disclosed is an exhaust mixer (50) including a passage (54) extending from an inlet (56) to an outlet (58) that is coincident with a centerline axis of mixer (50). Several ridges (68) are circumferentially disposed about the axis and each flare away from the centerline axis relative to a direction along the centerline axis from inlet (56) toward outlet (58). Ridges (68) each define a corresponding one of several inner channels (74) radially disposed about passage (54) that each intersect passage (54) between inlet (56) and outlet (58). Several outer channels (84) are also radially disposed about passage(54) and are each positioned between a corresponding pair of inner channels (74). Ridges are each shaped to turn inner channels (74and outer channels (84) about the axis as ridges (68) extend along the indicated direction. Inner channels (74) diverge away from the axis and one another in this direction while outer channels (84) converge toward the axis and one another in this direction.

Abstract: An airfoil for a gas turbine engine includes a leading edge, a trailing edge, a tip plate, a first sidewall, and a second sidewall. The first sidewall extends in radial span between an airfoil root and the tip plate. Furthermore, the first sidewall defines a pressure side of the airfoil. The second sidewall is connected to the first sidewall at the leading and trailing edges, and extends in radial span between the airfoil root and the tip plate. The second sidewall defines a suction side of the airfoil. The tip plate includes at least one groove that extends substantially between the first and second sidewalls.

Abstract: An airfoil for a gas turbine engine includes a leading edge, a trailing edge, a tip plate, a first sidewall, and a second sidewall. The first sidewall extends in radial span between an airfoil root and the tip plate. Furthermore, the first sidewall defines a pressure side of the airfoil. The second sidewall is connected to the first sidewall at the leading and trailing edges, and extends in radial span between the airfoil root and the tip plate. The second sidewall defines a suction side of the airfoil. The tip plate includes at least one groove that extends substantially between the first and second sidewalls.