| 摘要 |
PURPOSE:To increase the heat transfer rate on the gas side, by providing a plurality of raisings to a fin which is slanted in the flowing direction of air flow in the upstream side of a heat transfer pipe, and the raisings slanted to the reverse direction, in the downstream side, respectively. CONSTITUTION:The raisings 14a-14c provided in the upstream side of an air flow among heat transfer pipes 12 are slanted in the direction 13 of an air flow, so that an air flow 19 is produced by the air collided against the raising 14a. The dead water areas 16 and 17 around fins are made small by the effect of an air flow 18. An air flow 20 which crosses over the raisings 14 is deviated and is turned to the direction to adhere to flat fins 10 again, interfered by an air flow 21 which rolls up the air flow 20 into the flow on the side of the after flow of a raising 14c, produces flows 22 and 24 having swirling component parts, respectively. The flows 22 and 24 collide against a raising 15b in the downstream area of an air flow among heat transfer pipes 12, deviating, interfered by an air flow 23, producing air flows 25 and 26, having stronger swirling component parts. A boundary layer of temperature is disturbed by those flows 25 and 26, so that the thickness of a layer is decreased and the heat transfer rate on the gas side can be increased. |
