Enhanced pool boiling heat transfer by adding metalized diamond in copper porous materials

Abstract

Pool boiling heat transfer has attracted great attentions in heat dissipation areas, because of its great heat dissipation capability. To enhance heat transfer performance, lots of special porous structures have been designed, while the thermal conductivity enhancement of materials applied in the porous structure is rarely carried out. In this work, by adding metalized diamond in copper porous structures to increase the structure thermal conductivity, good pool boiling performance was observed. We firstly treated diamond into metalized diamond by sintering nickel method, and then different diamond/copper porous tablets were prepared by cold pressing metalized diamond and electrolytic copper particles together. Then, the pool boiling curves and the corresponding bubble dynamics of the porous tablets were experimentally investigated. Results turn out that: There are good wettability and also small interfacial thermal resistances between diamond and copper in the porous tablets, because of the metalized treatment of diamond. Thus, the boiling heat transfer could be significantly increased by 25%, compared to the tablets without treatment. There is a critical size of diamond to enhance the thermal conductivity of the porous tablets, because a small size of diamond always suggests large thermal resistances between diamond and copper, while a large size of diamond particle will lead to a bad metallization of diamond. In this work, the tablet prepared with 170-mesh size diamond possesses the highest pool boiling heat transfer, which could be more than 50% times larger than that of the smooth copper surface.