| 摘要 |
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 even bent lines of the upper and lower parts of profile shape. Also, blade shape in plane converges to the butt part of the working wheel blade. Aerodynamic profile in the normal section to lengthwise axis of the blade has length of the chord L at the end of the blade equal to 0.56 to 0.60 of length of chord L at the section of the blade positioned at 0.49 to 0.50 of length of the blade S. In the middle of the blade in normal section to lengthwise axis of the blade aerodynamic profile has a section with maximal thickness of profile equal to from 0.11 to 0.12 of chord length L in this cross section and positioned at distance of 0.32 L to 0.33 L measured from the front edge of profile along its chord. Notably, the line of the upper part of aerodynamic shape is convex relative to the chord, while the line of the lower part of aerodynamic shape is convex relative to the chord from the side of the front edge smoothly conjugated with concave from the side of the of the back edge. It crosses the cord in the middle of the blade behind cross section with the maximal thickness of profile in the direction from the front edge with an even increment of the convex part, as cross section transfers from the end of the blade to the middle and as it successively and evenly diminishes at transfer to the transition part. Also, angle of attack is smoothly changes from maximal at the beginning of the transition part to 0 at the end of the blade. An end wing is mounted on the end of the blade perpendicular to the lengthwise axis of the blade. Length of the end wing is less, than chord length, while length of the section of aerodynamic profile projecting from the side of the front edge is (0,12-0,15)L in the point of end wing installation. ^ EFFECT: raised efficiency and stability of cooling stack operation. ^ 4 dwg |
