Heat exchanger using the inner-grooved heat transfer tube and inner-grooved heat transfer tube

摘要

PROBLEM TO BE SOLVED: To provide a heat transfer tube with grooved inner surface, in which an inner surface fin does not fall down during expanding the tube, and which is suitable for a heat exchanger using carbon dioxide as a refrigerant.;SOLUTION: A heat transfer tube with grooved inner surface for use in an heat exchanger, comprising fins formed on the tube inner surface, wherein a first fin has a height of 0.10 mm to 0.22 mm, an apex angle of 20° to 60° and a ratio of the curvature radius to height of the top part of 5 or more, or a ratio of the width of a plane part to fin height of the top part of 0.3 to 1.0; a second fin has an apex angle of 20° to 60° and a height ratio of the first to second fins of 0.5 to 0.9; the thickness "t" of the pipe is 0.4 mm or more, and the ratio t/D of the thickness "t" to an outer diameter "D" ranges from 0.04 to 0.25.;COPYRIGHT: (C)2005,JPO&NCIPI