Fill ratio effects on vapor chamber thermal resistance with different configuration structures

The objective of this research is to present an investigation the thermal resistance of ten vapor chambers with different configuration structures with different working fluid fill ratios. The coolant flows entering the cooling section of the vapor chamber with constant mass flow rate of 0.05 kg/s. The de-ionize water is charged into the vapor space under vacuum condition with the ranging of 20-45% by volume. A 125 kW/m2 constant heat flux is applied at the 40 × 40 mm2 heat source area. It can be seen from experiments that the optimized fill ratio to obtain the minimum thermal resistance of the vapor chamber depends on the operating power, geometries and material types of heat sinks, configuration structures inside the vapor chamber. The results obtained from this study are expected to lead to guidelines that will allow designing vapor chamber with the optimized fill ratio to obtain minimum thermal resistance.