Simulation study on cooling effect of two-phase liquid-immersion cabinet in data center

Abstract

• When the inlet velocity is greater than 0.6 m/s, the two-phase immersion cabinet using Novec 649 can ensure the normal operation of the chip. • After using Novec 7000, a maximum decrease in the chip average temperature is 17.32 °C. • The horizontal baffle between the upper and lower chips can significantly reduce the maximum temperature difference of upper chip, with a maximum decrease of 31.37%. Two phase immersion liquid cooling cabinet can meet the cooling needs of high-density data center. However, the cabinet has the problem of poor heat dissipation effect caused by evaporation pressure fluctuation. The two-phase liquid-immersion cabinet with external condenser can discharge the generated vapor in time to maintain its pressure stability. But its cabinet-scale thermal management performance has not been investigated in detail yet. In this paper, the cabinet simulation model is established to evaluate the effects of inlet velocity, coolant type and cabinet internal structure on chip cooling effect from two aspects of thermal safety and temperature uniformity. The results show that the inlet velocity and the coolant type have great influence on the chip safety. When the inlet subcooling degree is constant, the drop range of chip temperature decreases gradually with the increase of coolant flow rate. The decline range is almost unchanged when the inlet velocity is greater than 0.6 m/s. At the same inlet subcooling degree and velocity, compared with Novec 649, the chip temperature decreased significantly after using Novec 7000 with lower boiling point. And the latent heat of vaporization also affected the temperature drop range, the average chip temperature decreased by 17.32 °C at most. The horizontal baffle between the upper and lower chips can significantly improve the overall temperature uniformity of the cabinet. Under the design conditions, the temperature uniformity coefficient of chip can be decreased by 55.64%, which is conducive to its safe and stable operation.