| 摘要 |
PURPOSE:To generate turbulent flow at the fore tip end of a flat plate fin to improve heat transfer performance and restrict noise generated at the rear end of the flat plate fin by providing the groups of cut-and-raised parts having specified configurations at specified positions on the surface of the flat plate fin. CONSTITUTION:A fin 1 is provided with total 6 rows of cut-and-raised pieces consisting of three rows of the same between two heat transfer tubes 2 neighboring in the direction of a stage at the upstream side of the flow A of air and three rows of the same arranged at the downstream side of the flow A of air in the same manner. The cut-and-raised pieces at the most upstream end of the airflow and the most downstream end of the same are separated respectively by central flat parts 3a and are constituted of two pieces of cut-and- raised pieces 14, 24. The cut-and-raised pieces in other rows are constituted of one piece of cut-and-raised piece 4 respectively. Respective openings 8, 18, 28 of the cut-and-raised pieces in six rows are orthogonal to the main flow direction (l) of the airflow. The cut-and- raised pieces 5, 6, 15, 25 are provided with directional slant angles substantially along lines extending in parallel to the tangential lines (m) of the outer periphery of the heat transfer tube 2 while raised parts 16, 26 at the side of the center of tube are arranged in parallel to the raised parts 15, 25 while the cut-and-raised pieces 14, 24 are formed so as to form a parallelogram.
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