Patent ID: 11761714

Abstract:
A fin, comprising: multiple fin subunits arranged in multiple rows, the fin subunits in two adjacent rows being arranged in an offset fashion. Each of the fin subunits comprises: a first direction center line and a second direction center line perpendicular to the first direction center line; a hole located at a central part of the fin subunit; four fenestrated zones, with two adjacent fenestrated zones in the four fenestrated zones being arranged as mirror images of each other, centered at the first or second direction center line therebetween; a flat zone comprising a hole periphery flat zone, the hole periphery flat zone being disposed between the hole and each fenestrated zone; each fenestrated zone comprises first, second, third and fourth boundaries, wherein the first boundary is located at that side of each fenestrated zone which faces the hole, the second boundary is located at that side of each fenestrated zone which faces away from the hole, and the third and fourth boundaries extend in a direction parallel to the first direction center line; the first boundary forms a demarcation line between the hole periphery flat zone and each fenestrated zone, and at least a portion of the first boundary is an elliptical arc or a circular arc that is not concentric with the circle center of the hole.