Hot-spot cooling using microliter liquid drops

In this paper, a new concept is developed for cooling integrated circuits (IC) in the electronic and computer industries. Microliter liquid drops are employed in combination with the electrowetting phenomenon to form a thermal conductance regulating interface (TCRI) between the heat-sink and the cooling target. An experimental setup was arranged in which a mercury drop could be attached to/detached from the surface of a hot-spot and, hence, influence its temperature. In addition, an in-house numerical code was developed to further investigate various parameters of the cooling system. The Navier-Stokes and energy equations were solved in a 2D/axisymmetric domain and the volume-of-fluid (VOF) technique was used to track the deformation of the free surface of the drops under the effect of the electrowetting phenomenon. Finally, as a sample case, a 4 × 4 array of mercury drops was considered to form a TCRI between a cooling target with non-uniform heat flux and a heat-sink. It was shown that the TCRI can be used to effectively suppress hot-spots on the surface of the cooling target. Various parameters of the cooling system were also examined.