In this paper an analysis of the fluid flow and the heat transfer in the next generation micro-sized heat sinks is presented. The analysis includes three different geometries for the channels of the heat sinks: rectangular, triangular and trapezoidal, with water as the cooling work flow. A constant heat flux typical of the current high-intensive computational chips (such as the current Pentium chips) is applied at the bottom of the heat sink in a small 1 cm × 1 cm area, an area also typical of the current contact area between electronic devices and the heat dissipaters. The analysis aims to determine the effect of geometry at microscopic scales. It is found that the temperature at the bottom of the dissipater increases approximately in a linear fashion and that by increasing the Reynolds number this temperature decreases. On the contrary, by having a decay in the Reynolds number the temperature of the working fluid increases, bringing a decrease in the viscosity allowing in turn a decrease in the friction losses since the friction coefficient decreases.
