Session: 02-02 Immersion Cooling II

Paper Number: 99137

99137 - Experimental Investigation of the Heat Transfer Characteristics of Aluminum-Foam Heat Sink Immersed in Dielectric Synthetic Fluid 

The power density of the processing unit has been increasing steadily with the advancement of microelectronic packaging. Due to the increase in power density and heat generation, more efficient cooling technology is required to enhance the reliability of the components and servers in the data center. Among all the cooling technologies, immersion cooling is one of the best performing technologies in terms of acquiring lower power usage effectiveness (PUE). In this study, conventional heat sinks have been replaced with high porosity metal foam heat sinks. High porosity metal foams are used in many applications due to their interconnected hollow structures which permit fluid to flow easily, enhance flow mixing capability, higher surface area in the same volume, and higher heat transfer area to volume ratio. The objective of this study is to experimentally investigate the thermo-fluid characteristics of aluminum foam heat sink when immersed in a dielectric synthetic fluid (EC 100). Metal foam with a relative density of 10-12% (85% porosity) and 5 pores per inch (PPI) was used in this experiment and subjected to different flow rates, heat flux, and inlet temperatures. Factors affecting heat transfer and fluid flow behavior such as geometrical (porosity and PPI) and operating (heat flux, inlet temperatures, and flow rates) were analyzed and discussed. 

In this study, the heat transfer experiments were carried out to assess the thermal-hydraulic performance of 5 PPI foam metal foam. The inlet temperature was maintained constant throughout experiments, but the flow rate and power varied from 0.2 to 0.8 lpm and from 100 to 250W, respectively. The Agilent 34972A data acquisition system was used in conjunction with the Data acquisition software for continuous temperature monitoring and data reporting in real-time. After reaching a steady-state, the sample rate for all temperatures, flow rate, and pressure data in the program was recorded every 10 seconds for the duration of the experiment. After each experiment, the heater's power source was turned off, and the system was allowed to cool until the inlet and outlet fluid temperatures are the same. When the system reaches a steady-state at no-load, the next set of experiments begins by giving power to the heater, and the data collection method is repeated.

The experimental data on the heat transfer characteristics of aluminum-foam heat sink immersed in the dielectric synthetic fluid is presented. The results show that a 5 PPI of 10-12 % relative density metal foam heat sink can maintain the surface temperature of the heater less than 85 °C at 0.8 lpm for a fluid input temperature of 20 °C and a power of 300 W. Similarly, if the flow rate is increased by more than 1 lpm, the heater temperature may be maintained at 85 °C for 250 W for inlet temperatures of 30 °C and 40 °C. Future research might look at the impact of geometrical and morphological characteristics such as metal foam thickness, porosity, and pore density on fluid flow and heat transfer performance. 

Presenting Author: Pratik Bansode The University of Texas At Arlington