Skewed axial fan assembly

A free-tipped axial fan assembly comprising:

• a fan rotatable about an axis and having a radius R and a diameter D, the fan comprising a hub, the hub having a radius Rhub, and a plurality of blades extending generally radially from the hub, each of the plurality of blades having a leading edge, a trailing edge, a blade tip, and a span S equal to the difference between the fan radius R and the hub radius Rhub;
• and
• a shroud comprising a shroud barrel surrounding at least a portion of each of the plurality of blade tips, a tip gap being defined between the shroud barrel and the blade tips,
• wherein each of the plurality of blades has a geometry, as viewed in axial projection, which at every radial position has a leading-edge skew angle and a trailing-edge skew angle, the leading-edge skew angle having a maximum value, and the difference between the maximum value of the leading-edge skew angle and the leading-edge skew angle at the fan radius R being at least 10 degrees,
• wherein the trailing-edge skew angle has a maximum value, and the difference between the maximum value of the leading-edge skew angle and the leading-edge skew angle at the fan radius R is at least 2.5 times the difference between the maximum value of the trailing-edge skew angle and the trailing-edge skew angle at the fan radius R, and
• wherein the fan radius R is measured at the trailing edge in the case of a fan with flared blade tips, and in the case of a locally-rounded blade tip at the trailing edge, is measured at the point where the tip gap is at a substantially minimum value.