| 摘要 |
PURPOSE:To provide high thermal conductivity throughout a whole range of from a fin on the upper stream side to a fin on the downstream side, by a method wherein, a front edge part is positioned opposite to an air current, a slit piece, having a rise surface inclined based on the direction of an air current, is risen from a fin surface, and the reference surface, which is left non-risen, of the fin is inclined based on the direction of an air current. CONSTITUTION:Fins 4 are situated between straight tube 1' of a flat tube 1, and are secured in a waveform manner to the flat tube 1 at intervals of a specified distance. The slit piece 5 is formed by rise from the surface of the fin 4, a front edge part 5' is positioned opposite to an air current direction B, a rise surface 5'' is inclined at a specified angle theta with the air current direction B, and the slit pieces 5, each having a width C, are continuously formed. Further, a reference surface 6, positioned between the slit pieces 5 and left non-risen, of the fin 4 is also formed so as to have a specified angle theta with the direction B and a width C. When heat exchange takes place between the air current B and a heating medium flowing through the flat tube 1, development of a temperature boundary layer (d), formed on the surface of the fin 4, of the air current B is disconnected, and the boundary layer (d), leaving a tail, is prevente from extending to the slit piece 5 and the reference surface 6 on the downstream side.
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