The effect of the thermal conductivity of room-temperature-vulcanizing silicone used for boiling heat transfer

Abstract

Boiling heat transfer (BHT) is expected to be a cooling technology for next generation electronic devices because it can remove a large amount of heat from a heating surface using latent heat of vaporization. However, there are two big problems in BHT: critical heat flux (CHF) and vibration. When the heat flux exceeds CHF, film boiling occurs and it causes rapid increase of the temperature of the heating surface. At this time, electronic devices will be damaged or broken because of a high temperature. To perform BHT safely, therefore, a heat spreader is needed to decrease the heat flux less than CHF. To increase heat transfer coefficient (HTC), moreover, the heating surface should be contacted with a coolant directly while keeping high electrical insulation. On the other hand, boiling bubbles are generated and collapsed repeatedly in BHT, and it causes the vibration of the cooling system. Therefore, it is difficult to use a rigid adhesive for BHT cooling devices. Room-Temperature-Vulcanizing (RTV) silicones, which is elastomer, are typically used to connect the heating surface with vessels for BHT. However, the thermal conductivity of RTV silicone is usually low. In this study, the effect of the thermal conductivity of RTV silicone for BHT is investigated by thermal conductivity analysis.