Blades (20a to 20c) of a propeller fan (10) have different circumferential pitches φ1, φ2, and φ3. The blades (20a to 20c) have different masses so that the center of gravity of the propeller fan (10) is positioned on a rotational center axis (11) of the propeller fan (10). Blade body portions (42c) of the blades (20a to 20c) have different thicknesses. In contrast, camber lines of the blades (20a to 20c) in blade cross section have the same shape, projections of the blades (20a to 20c) on a plane perpendicular to the rotational center axis (11) of the propeller fan (10) have the same shape, and leading edge portions (41a to 41c) of the blades (20a to 20c) have the same shape. As a result, a propeller fan (10) having reduced noise and vibrations can be achieved.

A turbine nozzle assembly system includes a plurality of nozzle sets, where each nozzle set forms an annulus. The nozzles in each set include an inner endwall and an outer endwall that include joint openings to receive the respective endwall mount ends of an airfoil. The airfoils across the plurality of nozzle sets have an inner endwall mount end and an outer endwall mount end that are identical amongst the plurality of nozzle sets. A wing portion of the airfoil has a selected wing shape that is identical within the respective nozzle set but different amongst the plurality of nozzle sets. In this manner, the endwalls can be removed from an airfoil and replaced with an airfoil having a different wing shape that provides a different pairwise throat area. The system allows changing of a pairwise throat area for a nozzle set without replacing the entirety of each nozzle.

A blisk fan is provided for a turbine engine propulsion system. The blisk fan includes a hub configured to rotate about a rotational axis at a maximum rotational speed, and a plurality of blades extending radially outward from the hub to define a fan leading edge tip diameter. Each of the blades has a first vibratory mode at a natural frequency, which is greater than a first fan order and less than a second fan order at the maximum rotational speed. The compression system preferably has a balance factor of the compression system between 1.9 and 3.2.

An impeller includes Z blades, where Z is an integer equal to 5 or more, arranged in a circumferential direction of the impeller and extending radially, and pitch angles between adjacent blades are all different. In terms of an arbitrary pitch angle θ, when a pitch angle α1 adjacent to the pitch angle θ, and a pitch angle α2 adjacent to the pitch angle θ, different from the pitch angle α1, satisfy a relation, α1<α2, a pitch angle β1 different from the pitch angle θ adjacent to the pitch angle α1 and a pitch angle β2 adjacent to the pitch angle α2, different from the pitch angle θ, satisfy a relation, β2<β1.

Flutter-resistant transonic turbomachinery blades and methods for reducing transonic turbomachinery blade flutter are provided. The flutter-resistant transonic turbomachinery blade comprises a transonic turbomachinery blade that includes opposite pressure and suction surfaces extending longitudinally in span from a root to an opposite tip, and extending axially in chord between opposite leading and trailing edges. The flutter-resistant transonic turbomachinery blade includes a local positive camber in or proximate a predicted local region of supersonic flow over the transonic turbomachinery blade. The method comprises predicting a local region of supersonic flow over the transonic turbomachinery blade and inducing the local positive camber to the transonic turbomachinery blade in or proximate the predicted region of supersonic flow.

A circular row of non-uniformally spaced vanes includes only one first group and only one second group of adjacent vanes, unequal first and second spacing between adjacent vanes in the first and second groups, and first spacing greater than second spacing. An embodiment with second group including only three adjacent vanes. Second spacing may be about 25%-35% smaller than a nominal uniform spacing used as a design parameter for designing spacing of the non-uniformly spaced stator vanes. Circular row may be sectored. A gas turbine engine section may include one or more rings or circular rows of fixed and/or variable non-uniformally spaced vanes. Method for designing non-uniform vane spacing for circular row includes determining nominal uniform spacing and forming first spacing and second spacing from nominal uniform spacing of vanes.

An impeller includes Z blades, where Z is an integer equal to 5 or more, arranged in a circumferential direction of the impeller and extending radially, and pitch angles between adjacent blades are all different. In terms of an arbitrary pitch angle θ, when a pitch angle α1 adjacent to the pitch angle θ, and a pitch angle α2 adjacent to the pitch angle θ, different from the pitch angle α1, satisfy a relation, α1<α2, a pitch angle β1 different from the pitch angle θ adjacent to the pitch angle α1 and a pitch angle β2 adjacent to the pitch angle α2, different from the pitch angle θ, satisfy a relation, β2<β1.

An impeller includes Z blades, where Z is an integer equal to 5 or more, arranged in a circumferential direction of the impeller and extending radially, pitch angles between adjacent blades being all different. In terms of an arbitrary pitch angle θ, when a pitch angle α1 adjacent to the pitch angle θ, and a pitch angle α2 adjacent to the pitch angle θ, different from the pitch angle α1, satisfy a relation, α1<α2, a pitch angle β1 different from the pitch angle θ adjacent to the pitch angle α1 and a pitch angle β2 adjacent to the pitch angle β2, different from the pitch angle θ, satisfy a relation, β2<β1.

A centrifugal fan includes: a main plate; and a plurality of blades extending from the main plate in the rotation-axis direction. The plurality of blades include, at least partially, an arrangement in which intervals between the adjacent blades are unequal intervals. A length direction of each blade extends from an inner circumferential side to an outer circumferential side of the main plate. In a pair of the blades adjacent to each other with a smallest interval in a rotation direction among the plurality of blades, the blades positioned on a backward side and a forward side in the rotation direction are different in outer-circumferential-side shapes, and an action of discharging a fluid toward the outer circumferential side by the blade positioned on the backward side in the rotation direction is made smaller as compared to the blade positioned on the forward side in the rotation direction.

An impeller includes a hub and blades. In radial direction, an upper surface of the blade near the outer edge includes a groove structure, a lower surface of the blade relating to the groove structure includes a peak structure, the lower surface of the blade includes a recess structure aside the trailing edge or the leading edge. The recess structure is connected to the peak structure. The blade has at least five airfoils from the inner edge to the outer edge. The blade is defined by continuously connecting the at least five airfoils at different sections in sequence so as to form the groove structure and the peak structure respectively on the upper surface and the lower surface. The groove structure and the peak structure are aside the outer edge of the blade.