| 摘要 |
A heat transfer tube with a cross-grooved inner surface used in refrigerators, air conditioners or the like and a manufacturing method thereof are disclosed. The heat transfer tube is formed in such a manner that the helix angle alpha of a primary spiral groove to the longitudinal axis of the tube is in the range of 10 DEG to 40 DEG , the intersecting angle beta of a secondary groove to the primary spiral groove is in the range of 75 DEG to 105 DEG , the ratio H/Hf of a height H of the secondary groove to a height Hf of the primary spiral groove is in the range of 0.5 to 1.0, the slope angle gamma 1 of an upstream slant face is in the range of 90 DEG to 105 DEG to the direction of the primary spiral groove, the slope angle gamma 2 of a downstream slant face is in the range of 30 DEG to 60 DEG to the direction of the primary spiral groove, and the ratio A/B of a width A of an upper surface of the ridge formed between the primary and secondary grooves to a width B of an upper opening portion of the secondary groove is in the range of 0.2 to 1.0.
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