EXPERIMENTAL INVESTIGATION OF VAPOR CHAMBER WITH DIFFERENT WORKING FLUIDS AT DIFFERENT CHARGE RATIOS

摘要

A vapor chamber is one of highly effective thermally transmission techniques in electronic cooling. We have evaluated the thermal performance of a 2.0 mm high, 50 mm diameter vapor chamber with water and methyl alcohol at different charge ratios. Also, solutions of water and propylene glycol at two concentrations (50% and 15%) were tested to study the effect of using a surfactant as an enhancement agent for the working fluid. The three types of thermal resistance of the chamber (junction resistance, internal resistance, and condenser resistance) were investigated to determine which type has the greatest effect on chamber total thermal resistance. The results show that water as a working fluid is much better than methyl alcohol. A charge ratio of 30% is best for most tested working fluids. Using a surfactant with water is much better than using only water. As the concentration of surfactant (propylene glycol) increases, the total thermal resistance of vapor chamber does not greatly change. The junction resistance is about 90% of the total thermal resistance of the vapor chamber. Reduction of the total thermal resistance process should focus on reducing junction resistance through enhancement of the evaporation process.