An axial fan includes an impeller that is provided with a blade that rotates around a central axis extending in a vertical direction, a motor unit that rotates the impeller, and a housing that is provided closer to a radially outer side than the impeller and surrounds the impeller. The impeller is further provided with an assist blade that protrudes at least in an axial direction from a radially outer end portion of the blade and extends in a circumferential direction. The assist blade is provided with a variable width portion at which an assist blade width between the blade and a tip end portion of the assist blade in a direction in which the assist blade protrudes decreases toward a rear side in a rotation direction from a front side in the rotation direction.

A fan blade for a gas turbine engine is arranged such that for any two points on its leading edge that are in the radially outer 40% of the blade span and are radially separated by at least 5% of the blade span, the radially outer of the two points is axially forward of the radially inner point. The radius of the leading edge of a given fan blade at the hub divided by the radius of the leading edge of the fan blade at the tip is less than or equal to 0.3. Such an arrangement may result in an improved operability range.

A fan blade for a gas turbine engine is provided with forward axial lean. The fan blade may have a substantially straight leading edge. The geometry of the fan blade results in a lower susceptibility to flutter, thereby allowing a gas turbine engine comprising such a fan blade to operate over a wider range of operating conditions.

A blade for an industrial axial fan includes an extruded or pultruded airfoil, extending along a blade axis and having a leading edge, a trailing edge, a root side and a tip side, an intrados and an extrados. A terminal member is arranged to close the tip side and has a rounded front portion in a plan view at the leading edge and a rounded rear portion in a plan view between the front portion and the trailing edge.

A propeller fan, including: a boss; and a plurality of blades, each of the plurality of blades including a pressure surface and a suction surface, in which: when a connecting portion between the pressure surface and a side surface of the boss is defined as a pressure surface-side boundary portion, and a connecting portion between the suction surface and the side surface of the boss is defined as a suction surface-side boundary portion, a curvature of the suction surface-side boundary portion is smaller than a curvature of the pressure surface-side boundary portion; and as a blade area projected on a plane orthogonal to the rotation axis, a blade area of the suction surface is larger than a blade area of the pressure surface.

The aspects described herein enable improved axial airflow along the entire length of the blades of a fan. The fan includes a hub with fan blades extending therefrom. Each fan blade couples to the hub and includes a proximal end, a distal end, a leading edge, and a trailing edge. Each fan blade is non-uniform, twisted, reverse-swept, and non-airfoil. The width at the proximal end is greater than the width of a fan blade at the distal end. The twist begins at the neck at the proximal end of the fan blade and continues along the length of the radius toward the distal end. The thickness of each fan blade along its chord width remains approximately the same, and thus non-airfoil. As a result, the fan provides axial airflow along the entire length of each fan blade, instead of just outer regions of the fan blades.

Rotor of a gas turbine engines having a rotor hub and a plurality of blades extending from the rotor hub, wherein each blade has a full-span forward sweep along a leading edge of the blade that starts at an airfoil root of the blade at the hub and extends to a blade tip, wherein a sweep of a blade is a percentage of a root axial chord length of the respective blade.

A ventilation blower wheel (1) comprising a hub (2) and blades (3) extending radially outwards from the hub (2) between a blade root (3a) and a blade tip (3b), the blades of said blower wheel having a backward/forward curvature as a result of a reversal in curvature along their span, characterized in that said blades (3) comprise, between 20% and 80% along their span, at least one pitch variation, extending over a maximum span distance of 25%, of at least 2 more or less than a linear pitch over said span distance.

A blade for an industrial axial fan includes an airfoil, extending along a blade axis and having a leading edge, a trailing edge, a root side, a tip side; and a rod, having a first end connected to the airfoil and a second end protruding from the airfoil for coupling to a hub. The root side has a rounded contour with a concave stretch adjacent to the leading edge and a convex stretch adjacent to the trailing edge. A root end of the leading edge protrudes with respect to the insertion point toward the second end of the rod in a direction parallel to the blade axis. The airfoil forms a lobe that extends in the direction parallel to the blade axis toward the second end of the rod more than with respect to the root end of the leading edge. The airfoil is extruded or pultruded and the leading edge is rectilinear and parallel to the blade axis.

A blade for an industrial axial fan has a first wing-shaped body having a first leading edge and a first trailing edge; a second wing-shaped body having a second leading edge and a second trailing edge inclined with respect to said keying axis and the first leading edge and the second trailing edge; and a third wing-shaped body having a third leading edge and a third trailing edge inclined with respect to said keying axis in the opposite direction to the inclination of the second leading edge and to the second trailing edge so as to define an entry vertex between the second and third leading edges.