To restrict pressure loss while improving heat exchange performance, by forming a slope on the root side of a part of a refracted part formed in a zigzag manner peripherally of a metal pipe internal peripheral surface.
Fins 2 are formed on an internal surface grooved heat transfer pipe 1 extending in the peripheral direction of the internal peripheral surface continuously replerected in zigzag, and a slope 10 extending rising from an internal peripheral surface of a metal pipe to an apex of a fin refracted part is formed on a root side of at least one part of the refracted part of these fins 2 (a side less than 118°C in a refraction angle). For this, even when a fluid flowing in the heat transfer pipe 1 flows in, concentrating at the fin refracted part, the fluid can get over the fin refracted part along a mild slope surface of the slope 10, and hence high fluid resistance is prevented from being produced. Further, since there is performed stirring of a fluid effective upon getting over the fin refracted part, pressure loss is reduced while keeping high heat exchange efficiency.
| JPH02176361 | HEAT EXCHANGER |
| WO/2012/136765 | EXHAUST GAS COOLER |
KOUCHI TETSUYA
KIKUCHI KOKORO
SUKUMODA TOSHITSUKA
