| 摘要 |
PURPOSE:To improve evaporating or condensing performance in a tub by a method wherein the side surface of a groove provided on the internal surface of the tube is provided with a plurality of auxiliary grooves with a given pitch so as to increase the area of the internal surface. CONSTITUTION:A plurality of spiral grooves 2, separated by rib-like protuberances 1, are provided continuously on the internal surface of the tube while auxiliary grooves 3, smaller than the groove 2, are provided on the side surface of the upstream side with respect to the flowing direction of refrigerant from the bottom surface side of the groove to the depthwise direction of the groove with a given pitch. Here, the auxiliary groove 3 may be provided on the both side surfaces of the groove 2. The groove 2 or the protuberances are provided on the internal surface of the heat transfer tube of such constitution, therefore, gas refrigerant 5 and liquid refrigerant 4 becomes the condition of being mixed and the evaporation of the refrigerant may be promoted. |
