| 摘要 |
PURPOSE:To provide a heat transfer tube of a high heat efficiency which is easy to manufacture by closely fixing a thin tubular body made of copper or a copper alloy, having a diameter dimension substantially equal to the inner diameter of the tubular body, to the inner surface of the tubular body having a smooth inner surface or a grooved tubular body. CONSTITUTION:A copper tube 2 provided with a large number of through holes 2a is defatted washing with trifluoroethylene, and inserted into a copper tube 1. Thereafter, idle elongation is carried out and cold drawing is also carried out and a copper tube 1 attempted to be integrally formed with the porous copper tube 2, and metal cores are inserted into double tubes 1 and 2 to thin the thickness of the copper tube 1 thereby to carry out metal core extraction. As a result, the through hole 2a is elongated in the direction of the extraction axis, and is deformed in an oval hole, and its closely holding force is extremely increased. Further, as a result, the heat transfer area becomes large, and nucleate boiling, capillary tube phenomenon and turbulent flow are easy to occur, and thus the heat transfer efficiency is increased. |
