Simulation of the Fluid Dynamics in an Active Liquid Heat Sink for CPU Cooling System

S.-H. Wang, S. Melendez, M. Gomez
Micro and Precision Manufacturing Center, Kun-Shan University of Technology, Taiwan

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, 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, can be well over five times the average velocity. Since convective heat transfer is largely dependent on liquid velocity, much higher cooling efficiency is expected, especially in the neighborhood of the impeller that could be located on top of the CPU heat source.

The simulation also reveals that, with increase of impeller rotational speeds, the velocity as well as the flow rate increase almost linearly. This result is very useful for the design and optimization of the cooling system.