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. It is made in form of hollow case and consists of a butt end corresponding to a round rod designed for fixing the blade to a hub of a working wheel of the fan. The blade is set at required angle. Further, the blade consists of a wing and transition part from the butt to the wing. The latter is profiled and is formed with aerodynamic profile of chord of alternate length L along lengthwise axis of the blade. The blade has rounded front edge and a sharp or dull back edge on the ends of profile chord interconnected with smooth lines of an upper and lower parts of profile shape. In plane the shape of the blade converges to the middle of the blade wing and expands from the middle to the end of the blade. The front and the back edges are concave to the lengthwise axis of the blade. The transition part of the blade step-by-step converges in the direction to the butt end of the working wheel blade. Aerodynamic profile in normal cross section to lengthwise axis of the blade in the middle of the blade wing has a section with maximal thickness of profile equal to 0.15-0.16 chord length L in this cross section and located at distance from 0.37·L to 0.38·L measured from the front edge of profile along its chord. The said section is positioned at distance S₁ from the end of the blade corresponding to from 0.40 to 0.42 from blade length S. Also, line of the upper part of aerodynamic profile is convex relative to chord, while line of lower part of aerodynamic profile relative to chord is convex from the side of the front edge and smoothly conjugated with concave one from the side of the back edge. It crosses chord behind cross section with maximal thickness of profile in the direction from the front edge. Further, maximal thickness of profile smoothly decreases from the transition part of the blade to the end from (0.22-0.24) L to (0.1-0.12) L. Angle of blade cross section setting at the end of the blade relative to plane of blade rotation is turned to the side opposite to angle of blade angle setting in the beginning of the transition part of the blade.

EFFECT: raised efficiency and stability of cooling stack operation.

3 cl, 5 dwg