| 摘要 |
PROBLEM TO BE SOLVED: To provide a heat transfer tube capable of improving a tube interior heat transfer rate while suppressing increase in pressure loss. SOLUTION: The heat transfer tube 11 which is provided with a spiral fin 12 formed on the tube inner face 10 and having a predetermined angle (β<SB>1</SB>) with respect to the tube axial direction D1 and 0.1-0.30 mm of height (H<SB>f</SB>) and with an outer diameter smaller than 7 mm includes fin configuration parts 12A formed by segmenting the fin 12 by a spiral auxiliary groove 14 having 0.1-0.30 mm (H<SB>n</SB>) of depth (H<SB>n</SB>). On at least the downstream side D2d in the spiral direction of the fin configuration part 12A, a projecting piece 16 protruded having 5°≤α<70°of an angle (α) with respect to the fin 12 is provided between the adjacent fins 12 on the upstream side D1u of the tube axial direction. The fin configuration part 12A is formed so that an interval (P<SB>f</SB>) between the fin configuration parts 12A in the fin forming direction is equal to or more than 1.5 mm and a ratio (W<SB>1</SB>/W<SB>2</SB>) of projecting length (W<SB>1</SB>) with respect to an interval (W<SB>2</SB>) of the projecting pieces 16 between the fins 12 is 0.3-0.9. COPYRIGHT: (C)2011,JPO&INPIT
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