Parametric invesstigation of liquid cooling module using FC-72

The effect of five parameters that affect the performance of a liquid cooling module; module orientation, charge ratio, charge temperature and air temperature have been investigated. The liquid cooling module was previously developed by the authors and comprised of an integrated assembly of a boiling plate, spacer, and condenser plate and used FC-72 as the working fluid. The size of the module was 101 mm times 108 mm times 18 mm and used a 1 cm² heat source. To enhance boiling performance, microporous coated pin fins were used on the boiling plate surface. Heat rejection from the module was achieved using a water-cooled cold plate. Results showed no significant effect of the module orientation on performance (as long as the boiling section was completely submerged). There appeared to be no significant effect of charge ratio (amount of FC-72) on the module performance in the vertical orientation, however, boiling performance was significantly affected by the charge ratio in the horizontal direction and was attributed to an increase in the flow resistance to the liquid rewetting the boiling surface (boiling surface not fully submerged). The charge temperature, which determined the amount of the air in the module, deteriorated both boiling and condensation performance and reduced the maximum attainable heat flux. As the cold plate inlet temperature decreased, the module thermal resistance increased, however, because the chip temperature was also decreased, the maximum obtainable heat flux was significantly increased. The chip temperature was limited to a maximum value of 100 degC