PURPOSE: To obtain a heat transfer wall whose boiling heat transfer property is improved through tunnels, by forming two layers of a plurality of fine tunnels that are located under each surface between grooves with a large pitch, are extended crossing with the grooves, and are formed integrally with a heat transfer wall and whose both ends are in communication with the grooves.
CONSTITUTION: A heat transfer pipe includes a heat transfer main pipe 1 having the helical grooves with a large pitch, and two rows of the plurality of fine tunnels 3, 4 are extended under each suface between the grooves 2 normally to the grooves 2 and are integrated with the main body 1. The inclinations of the rows of the tunnels 3, 4 may or may not the same to the grooves 2. The numbers of the tunnels in the rows may or may not the same. The opposite ends of the tunnels 3, 4 are open adjacent to the grooves 2, and are in communication with the outside via each of gaps 5. The inside of the pipe main body 1 may be smooth, but in this aembodiment, the parts corresponding to the grooves are projected helically. Accordingly, if the fluid in the pipe flows slowly, turbulence effect occurs, and the heat transfer efficiency in the pipe can be improved.
SASAKI SATOSHI
FUKUDA SHIGEO
KAKIZAKI KIMIO
NAKAYAMA HISASHI
OOGURO TAKAHIRO
NAKAJIMA TADAKATSU
NAKAYAMA YOSHIHIKO
HITACHI LTD