Experimental study of a single-phase immersion cooling system with natural and forced convection

The rapid advancement of the electronics industry has led to the emergence of miniaturized, high-speed devices with significant amount of volumetric heat generation. Immersion cooling systems offer an effective solution for managing high heat loads, particularly in data centers and battery thermal management systems. However, several fundamental issues of the underlying physical phenomena still need to be addressed to improve the efficiency of these systems. In this study, an immersion cooling system using Novec 7100 dielectric liquid has been experimentally investigated having four electric cartridge heaters with circular and square cross-sections. The effect of distance between heaters on the surface temperature was analyzed under different flow conditions. Furthermore, the effect of heater cross-section on the heat transfer coefficient was examined. For natural convection, the heat transfer coefficient increased as the distance between the heaters was increased for both heaters. As expected, the forced convection mechanism was found to be significantly more effective in heat removal compared to natural convection. At high heat flux values, the heat transfer coefficient was found to be higher for square heaters due to their 1.15 times larger surface area. However, for low heat flux values, the heat transfer coefficient was higher for circular heaters than the square heaters. These findings provide valuable insights into the optimization of immersion cooling systems, highlighting the influence of heater geometry and heater spacing on thermal management efficiency.