Experimental study on visualization of a longitudinal heat sink with top-mounted fan by particle tracking

The miniaturizations of electronic devices and the rapid increase in power density of electronic components have created a need for improved cooling technologies to achieve high heat-dissipation rates. The combination of top-mounted fan and longitudinal fin is the most popular module for CPU cooling of desktop computers. In this paper, some findings are presented from the experimental study aimed at obtaining the flow patterns inside the longitudinal heat sink in order to help in designing cooling modules. Experimental work of visualization is carried out in a water tunnel using theory of similarity analysis in fluid dynamics by a particle tracking method. Physical interpretation is based on the digital video images and pictures from the water-tunnel experiment. Results show that there are three types of flow patterns within the heat sink. Vortices are induced inside the longitudinal fin, especially at the center of the top-mounted fan. These vortices would reduce the heat transfer rate for the cooling module. The experimental result is also compared with that of numerical simulations using the commercialized software code ICEPAK.