| 摘要 |
PURPOSE:To provide a tube with smooth and efficient evaporating and/or condensing capacity at all times and obtain high heat transfer performance by a method wherein two pieces of projected parts are formed symmetrically to the center axis of the heat transfer tube while grooves are arranged symmetrically to each other from boundaries or the projected parts. CONSTITUTION:Two pieces of projected parts 3, 3' are formed symmetrically to the center axis of a heat transfer tube 1 while spiral grooves 2 are arranged and provided symmetrically to each other from respective boundaries or the projected parts 3, 3'. Accordingly, the flow of medium, existing at the bottom of the grooves at upstream side, is intercepted by the projected parts and liquid becomes splash and collides against the downstream side of the groove whereby the liquid, existing at that part, may be agitated. Heat transfer may be promoted remarkably by this effect in an evaporating process. At the downstream side of the groove, the condensed constituent of lubricating oil in the medium existing at the bottom of the groove is collected to the peripheries of the projected parts and flows to the axial direction of the tube whereby heat transfer may be promoted. In a condensing process, the liquid in the groove is flown by the flow of refrigerant vapor at every times when the liquid meets with the projected parts and the liquid, existing in the upstream side of the groove, is hindered by the projected parts whereby the liquid becomes hard to flow to the downstream side and the grooves contribute to the improvement of boiling heat transfer coefficient. |
