Simulation of the fluid dynamics in active liquid heat sink for CPU cooling system

This study numerically investigates the fluid dynamics in an active-liquid-heat-sink (ALHS) for a computer microprocessor cooling system. Principal concepts, basic design, and the integration of the ALHS technology into an internal CPU liquid cooling system are presented. Basic assumptions and numerical methods, especially for rotating machinery in fluid dynamics in the numerical simulation, are discussed in detail. From the numerical simulation, the stirring effect by the impeller on the velocity field is quite significant. The maximum velocity, which occurs in the vicinity of the impeller, is shown to be much larger than the average velocity. Since convective heat transfer is largely dependent on liquid velocity, higher cooling efficiency is expected; especially in the neighborhood of the impeller which could be located on top of the CPU heat source. Throughout the simulation, various impeller geometries were investigated, focusing on straight and curved leaves. The results indicated a higher flow rate with curved leaves, making their use favorable. Also, the simulation revealed that as the impeller rpm increases, both the velocity and the flow rate increase almost linearly. This result proves very useful for designing and optimizing of the cooling system.