Experimental and Numerical Study of Two-Phase Immersion Cooling for High-Power Chips

As the demand for high-performance computing continues to rise, so does the power consumption of semiconductor devices. How to cool these high-power chips efficiently and effectively has become a significant challenge.In recent years, immersion cooling technology has garnered increasing attention. Immersion cooling has advantages such as high heat transfer coefficients, high cooling capacity, low power consumption, and a compact form factor. The fundamental principle of immersion cooling is that electronic components, such as processors, are immersed in a dielectric liquid that is nonflammable. Heat is removed from the components directly through the dielectric liquid. According to the boiling point of the dielectric liquid, it can be divided into two approaches: single-phase and two-phase immersion cooling.This study adopts both a numerical and experimental approach to investigate the cooling of high-power chips by using a two-phase immersion cooling method.For numerical simulation, the six-equation Eulerian two-fluid model in OpenFOAM is adopted. In order to simulate the complex process of fluid boiling phenomenon, RPI heat flux partitioning model is chosen to simulate fluid boiling process. The model incorporates the momentum exchange term between the gas and liquid phases to account for differences in density and relative velocity.The two-phase immersion cooling experiment is performed in a 600mm x 450mm x 320mm tank with an 800W heat source, a condenser and a mesh type BEC (boiling enhancement coating). Fluorez FL-50 is adopted as working fluid for two-phase immersion cooling. The water inlet of the condenser is fed with a constant temperature chilled water. A pressure balancing device is implemented to maintain tank gas pressure around 1 atm. For comparing with numerical results, the liquid temperature around the chip, chip case temperature, gas temperature is measured in the experiment.In this study, a classical DEBORA test result of subcooled flow boiling is chosen to validate the numerical method first. In addition, a parametric comparison of numerical and experimental results of cooling high-power chips using a two-phase immersion cooling method is performed. The simulation and experimental results indicate that the difference in chip case temperature stays below 3.4% under steady-state condition.