Effects of structure characteristics and fluid on the effective thermal conductivity of sintered copper foam

Abstract

Heat exchangers with excellent heat transfer performance are highly demanded as the development of the powerful chips and integrated circuit. Due to the large surface area and good thermal conductivity, porous metal has become a potential candidate material for the future heat exchangers. A powder metallurgy-based method was used to manufacture copper foam samples with highly controllable particle size, porosity and pore size in this study. The effects of particle size, porosity and natural convection on the so-called effective thermal conductivity (ETC) of the copper foam and the heat transfer mechanism of copper foam-fluid system were experimentally investigated. The effect of natural convection was studied by comparing the ETC of the copper foam, copper foam-air and copper foam-water system. Results show that the thermal conductivity of sintered copper sample was strongly affected by the particle size of the starting copper powder. The medium particle size (45–70 μm) was ideal for obtaining the best thermal conductivity. The dependence of ETC on porosity can be properly described by the Power Law model. A linear correlation was also proposed to describe the effects of porosity and pore size on the contribution of the fluid to the metal foam–fluid system.

Keywords

• Effective thermal conductivity
• Copper foam
• Natural convection
• Cu powder sintering
• Porous media