| 摘要 |
PURPOSE:To completely divide growth of a temperature boundary layer and to enable maintenance of a heat transfer rate between an air flow and a fin at a high value, by a method wherein a cut-rise surface extending in parallel to the direction of an air flow is formed in a fin surface, and the height of the cut rise is changed in a stepped manner to form a meandering pattern. CONSTITUTION:Fins 5 are fixed in a corrugated manner to a heat transfer pipe 4 at intervals of a fin pitch. Cut rise surfaces 6 formed on both surfaces of the fin 5 are formed so as to extend in parallel to the direction of an air flow B. The height of the cut-rise surface 6 from the fin 5 is set to values in two stages of the one being 1/5 of a fin pitch and the other being 2/5 of the fin pitch. The cut-rise surface 6 in a five-stage is changed by 1/5 of a fin pitch at each stage to form a meandering pattern. Since, during heat exchange, an air flow B flows a flow passage where increase and decrease in a distance between the fins are repeated, a pressure difference is produced between both surfaces of the fin 5, and by dividing growth of the temperature boundary layer of the air flow B generated on the cut-rise surface 6, a heat transfer rate can be maintained at a high value.
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