Important factors affecting the thermal resistance and thermal diffusivity of vapor chambers

This paper discusses a number of important parameters associated with the measurement of thermal resistance and thermal diffusivity in vapor chambers (VCs). Thermal resistance and thermal diffusivity are representative indicators of VC performance. In this paper, we measured thermal resistance using four distinct Experiment Setups. Our empirical results demonstrate that thermal resistance values depend largely on how the experiment is set up. We also examined two different condensation methods in the measurement of thermal resistance. Condensation condition 1 uses cooling water with an input temperature fixed at 20 °C and the flow rate fixed at 10 g/s. Condition 2 involved fixing the temperature of the top surface of the vapor chamber by adjusting the temperature of the cooling water according to the input power. In experiments, the lowest thermal resistance was 0.135 °C/W under condensation condition 1 and 0.023 °C/W under condensation condition 2. We also developed a device for the measurement of thermal diffusivity based on the Angstrom method. We then measured (under experimental conditions) the thermal diffusivity of four pure metals for comparison with standard reference values. The thermal diffusivity values were measured as follows: VC (44.04 cm2/s) and copper plate (1.219 cm2/s).