| 摘要 |
PURPOSE:To contrive remarkable improvement of heat transfer rate by a method wherein a plate fin is formed with a multitude of upright slits, which are split upwardly and downwardly, on both surfaces thereof. CONSTITUTION:The base plate of the plate fin 11 remains on the center line (n) of a heat transfer tube 13, which is parallel to air stream B, while the plate fin is formed with the upright slits 11a-11d on both front and rear surfaces of the fin at the upper and lower parts of the center line (n) and the heights thereof are changed into two stages. The heights of the slits 11a, 11d are shown by (l1) while the heights of the slits 11b, 11c are shown by (l2). The fin 11 is formed with the slits on both front and rear surfaces thereof, therefore, the strength of the fin is improved remarkably. On the other hand, the heights of the slits are changed into two stages, therefore, turbulent flow is promoted, the temperature boundary layers of the force slits 11a, 11b are disappeared before the next upright slits 11c, 11d and development of the temperature boundary layers may be precluded sufficiently where by heat transfer rate may be improved remarkably. |
