An Experimental Study on Enhancing Cooling Rates of Low Thermal Conductivity Fluids Using Liquid Metals

Abstract

In a previous numerical study (Al Omari, Int. Communication in Heat and Mass Transfer, 2011) the heat transfer enhancement between two immiscible liquids with clear disparity in thermal conductivity such as water and a liquid metal (attained by co- flowing them in a direct contact manner alongside each other in mini channel) was demonstrated. The present work includes preliminary experimental results that support those numerical findings. Two immiscible liquids (hot water and liquid gallium) are allowed experimentally to exchange heat (under noflow conditions) in a stationary metallic cup where they are put in direct contact. The experimental results confirm the significant heat exchange enhancement. The superior thermal conductivity of the used liquid metal as compared with the water is the reason behind the observed enhancement in heat transfer. For the same residence time and the same contact surface area between the two liquids, however, the experiments show a slightly slower rate in the heat transfer between the two liquids compared to the case of the channel flow considered in the numerical simulations. This discrepancy is justified on the basis of the additional enhancements brought about by the forced convectional effects in the case of the channel flow (which are absent in the experiments where conduction and natural convection prevail).