PURPOSE: To enable the surface of a porous layer to have a high heat transfer capacity by a method wherein a number of grooves capable of varying regularly the rate of distribution of gaps in the surface of the porous layer are provided in a part of the surface.
CONSTITUTION: The porous layer is formed of a sintered particle layer 11 consisting of sintered particles 10 and the groove 12 are formed in the surface of the porous layer by pressing a knurling tool against the surface. As a result, large open holes 13 which act as active open holes, that is, air bubble developing holes, and small open holes which act as inactive open holes, that is, liquid adsorptive holes, are provided regularly in the heat transfer surface of the porous layer in a certain ratio so that the development of air bubbles and the adsorption of the liquid are stabilized and the boiling heat transfer efficiency of the heat transfer surface of the porous layer is improved. As regards the method of forming the grooves 12 in the surface of the porous layer, it is also possible to form the grooves by cutting in the surface with a bite or a metal saw instead of using the knurling tool such that the small open holes 14 are formed due to the stress generating with the cutting operation.
NAKAYAMA HISASHI
OOGURO TAKAHIRO
MORIMOTO TOORU
OOGAKI TOSHIHISA
NIPPON DIA CLEVITE CO
| JPS54111158A | 1979-08-31 |