High efficiency to diameter ratio and low weight axial flow fan

A high efficiency axial flow fan for producing an airflow through an engine compartment of a vehicle comprising:

• a hub rotatable about a rotational axis, a circular band concentric with the hub and spaced radially outward from the hub, and
• a plurality of fan blades distributed circumferentially around the hub and extending radially from the hub to the circular band, wherein each blade has substantially the parameters defined by
• __________________________________________________________________________ Range of R over R C .THETA. .xi. h .LAMBDA. which dh/dR is dh/dR (mm) (mm) (deg) (deg) (mm) (deg) measured (mm) (mm/mm) __________________________________________________________________________ 66.5 8.40 to 48.30 10.00 to 25.00 61.31 to 71.31 -25.98 3.00 to +3.00 66.5 to 72.0 -0.21636 72.0 8.40 to 48.30 10.50 to 25.50 56.94 to 66.94 -27.17 -3.00 to +3.00 72.0 to 91.0 -0.06579 91.0 8.55 to 49.16 16.27 to 36.27 55.56 to 65.56 -28.42 -1.69 to +4.31 91.0 to 104.0 -0.00308 104.0 8.82 to 50.69 13.50 to 28.50 58.85 to 68.85 -28.46 -1.70 to +4.30 104.0 to 17.0 -0.18462 117.0 9.46 to 54.39 11.00 to 26.00 60.50 to 70.50 -30.86 -2.87 to +3.13 117.0 to 24.0 -0.21429 124.0 9.03 to 51.92 10.00 to 25.00 62.80 to 72.80 -32.36 -4.39 to +1.61 124.0 to 30.5 -0.461538 130.5 8.60 to 49.45 10.00 to 25.00 67.50 to 77.50 -29.36 -5.89 to +0.11 -- -- __________________________________________________________________________
• wherein R is the radial distance in millimeters from the rotational axis;
• C is the chord length in millimeters at the radial distance R;
• .THETA. is the blade section camber angle in degrees at the radial distance R;
• .xi. is the blade section stagger angle in degrees at the radial distance R;
• .LAMBDA. is the skew angle of the chord section in degrees, at the radial distance R, calculated at 30% chord;
• h is the dihedral distance in millimeters of the downstream edge of the blade, at the radial distance R, from a plane perpendicular to the axis of rotation at the upstream surface of the hub;
• dh/dR is the slope of the dihedral measured between two adjacent values of R;
• and where the blade root position at the hub is defined as zero skew, and negative values of d.LAMBDA./dR indicate a forward skew.

A high efficiency axial flow fan for producing an airflow through an engine compartment of a vehicle comprising:

• a hub rotatable about a rotational axis, a circular band concentric with the hub and spaced radially outward from the hub, and
• a plurality of fan blades distributed circumferentially around the hub and extending radially from the hub to the circular band, wherein each blade has substantially the parameters defined by
• ______________________________________ Range of R over which R C .THETA. .xi. .LAMBDA. h dh/dR is dh/dR (m) (mm) (deg) (deg) (deg) (mm) measured (mm) (mm/mm) ______________________________________ 66.5 42.00 15.00 66.31 0 -25.98 66.5 to 72.0 -0.21636 72.0 42.00 15.50 61.94 0 -27.17 72.0 to 91.0 -0.06579 91.0 42.75 21.27 60.56 1.31 -28.42 91.0 to 104.0 -0.00308 104.0 44.08 18.50 63.85 1.30 -28.46 104.0 to 117.0 -0.18462 117.0 47.30 16.00 65.50 0.13 -30.86 117.0 to 124.0 -0.21429 124.0 45.15 15.00 67.80 -1.39 -32.36 124.0 to 130.5 -0.461538 130.5 43.00 15.00 72.50 -2.89 -29.36 -- -- ______________________________________
• wherein R is the radial distance in millimeters from the rotational axis;
• C is the chord length in millimeters at the radial distance R;
• .THETA. is the blade section camber angle in degrees at the radial distance R;
• .xi. is the blade section stagger angle in degrees at the radial distance R;
• .LAMBDA. is the skew angle of the chord section in degrees, at the radial distance R, calculated at 30% chord;
• h is the dihedral distance in millimeters of the downstream edge of the blade, at the radial distance R, from a plane perpendicular to the axis of rotation at the upstream surface of the hub;
• dh/dR is the slope of the dihedral measured between two adjacent values of R;
• and where the blade root position at the hub is defined as zero skew, and negative values of d.LAMBDA./dR indicate a forward skew.

A high efficiency axial flow fan for producing an airflow through an engine compartment of a vehicle comprising:

• a hub rotatable about a rotational axis, a circular band concentric with the hub and spaced radially outward from the hub, and
• a plurality of fan blades distributed circumferentially around the hub and extending radially from blade root at the hub to a blade tip at the circular band, wherein each blade has substantially the parameters defined by
• ______________________________________ .THETA. .xi. .LAMBDA. % span C/span (deg) (deg) (deg) h/span ______________________________________ 0.00 0.6563 15.00 66.31 0 -0.4059 8.59 0.6563 15.50 61.94 0 -0.4245 38.28 0.6680 21.27 60.56 1.31 -0.4441 58.59 0.6888 18.50 63.85 1.30 -0.4447 78.91 0.7391 16.00 65.50 0.13 -0.4822 89.84 0.7055 15.00 67.80 -1.39 -0.5056 100.0 0.6719 15.00 72.50 -2.89 -0.4588 ______________________________________
• wherein span is a distance from a blade tip to an associated blade root;
• C is the chord length at a % span;
• .THETA. is the blade section camber angle in degrees at a % span;
• .xi. is the blade section stagger angle in degrees at a % span;
• .LAMBDA. is the skew angle of the chord section in degrees, at a % span, calculated at 30% chord;
• h is the dihedral distance of a downstream edge of a blade, at a % span, from a plane perpendicular to the axis of rotation at an upstream surface of the hub.

A vehicle cooling system comprising:

• a heat exchanger configured to transfer heat from a vehicle system;
• and
• a powered fan constructed and arranged to move air past the heat exchanger, the fan including a plurality of radially-extending fan blades configured to produce an airflow when rotated about a rotational axis, each blade having a chord length distribution, stagger angle and dihedral distribution which varies along the length of the blade, each blade extending axially downstream from the upstream surface of the hub,
• wherein each blade joins a circular band concentric with the hub and spaced radially outward from the hub, and wherein the circular band comprises an upstream edge disposed substantially axially downstream from the upstream surface of the hub,
• and wherein the rate of change of the dihedral distance of the trailing edge of each blade with respect to a radius is variable and is substantially between 0 and -0.46.