Effect of Design Variables and System-Level Constraints on Heat Pipes Heatsink Performance: Part I - Component Materials and Heat Pipe Design Features

In order to investigate the limitations and the theoretical cooling limit of the heat pipe heatsink technology, a parametric study of high-performance heatsinks under different design and in-service constraints was conducted. Although the fluid dynamics and heat transfer of finned heatsinks are well-documented, both experimental and numerical investigations have focused on flowbench-type boundary conditions. Therefore, the impact of surrounding IT equipment, such as upstream electronics, CPU power map, etc., has not been considered for comprehensive design optimization. In the first paper, a computational model of a high-performance heat pipe heatsink has been developed to examine the effect of component material/composition and heat pipe design features on the heatsink performance. Particularly, the computational model was modified to allow different material for each heatsink component and a varied number of embedded heat pipes. Among the heatsink components, the heat pipe composition was found to be the feature with the greatest influence on the heatsink performance. A semi-empirical model to predict the heat pipe effective thermal conductivity was developed, and the relative performance improvement with respect heat pipe conductivity is presented. The effect of the number of heat pipes on the total heatsink thermal resistance was analyzed. A design trade-off in terms of heatsink impedance increase was presented as consistent thermal performance improvement with respect to number of heat pipes was observed.