BLADE OF COOLING STACK FAN Russian patent published in 2010 - IPC F04D29/38 F28F25/00 

FIELD: machine building.

SUBSTANCE: blade of cooling stack fan is made in form of hollow case and consists of butt part corresponding to round rod. It is designed for fixing the blade to a hub of a working wheel of the fan. The blade is installed at a required working angle. Further, the blade consists of a wing and of a transition part from the butt to the wing. The latter is profiled and formed with an aerodynamic profile with a chord of alternate length L along lengthwise axis of the blade, with a rounded front edge and with a pointed or dull back edge arranged on the ends of the profile chord and interconnected with flat lines of the upper and lower parts of profile shape. Also, blade shape in plane converges to the end part of the blade. The front and back edges are rectangular and inclined to lengthwise axis of the blade at angle α from 15° to 20°, while the back edge is made at angle β from 5° to 8°. Also, the transition part of the blade step-by-step converges to the butt part of the working wheel blade. Aerodynamic profile in normal section to lengthwise axis of the blade has a section of maximal thickness of profile positioned at the beginning of the transition part of the blade; the section is equal to 0.14-0.15 of chord length in this section and positioned at distance from 0.38·L to 0.40·L measured from the front edge of profile along it chord. The said section is located at distance S₁ from the end of the blade corresponding from 0.70 to 0.72 from length S of the blade. Further, line of the upper part of the aerodynamic profile is convex relative to the chord, while line of the lower part of aerodynamic profile is convex relative to the chord from the side of the front edge smoothly conjugated with a concave one from the side of the back edge forming a crescent shape. At the end of the blade the section with maximal thickness of profile equal to (0.10-0.12) L is positioned from the front edge of profile at distance equal to (0.38 to 0.40)L. An angle of setting section of the blade at the end of the blade in relation to plane of blade rotation is turned to a side opposite to the angle of setting of blade section at the beginning of the transition part of the blade.

EFFECT: raised efficiency and stability of cooling stack operation.

3 cl, 5 dwg