Two-phase electrohydrodynamics along a grooved flat heat pipe

The present communication reports on the investigation of the effect of an electric field on the performance of a flat plate heat pipe (FPHP). In the studied configuration, an electric stress is imposed on the liquid–vapor interface, which adds to the capillary force. The ability of the electric field to change the shape of the liquid–vapor interface is investigated by means of both a numerical and an experimental approach. The numerical approach consists in solving two strongly-coupled equations: the Laplace–Young equation and the Laplace equation for the electric potential; the latter being required to get the distribution of the normal electric stress along the meniscus, while the former is used to calculate the meniscus shape. The Laplace–Youngequation is modified accordingly to take into account the added contribution of the normal electric stress. The results of the numerical study for an application inside an FPHP are discussed. A possible enhancement of the capillary pumping is highlighted for a specific geometry of the electrode. The experimental approach is based on a test bench that consists in a tilted grooved aluminum plate equipped with a pair of horizontal electrodes filled with Novec HFE-7100 in liquid and vapor states. The effect of the electric field on the liquid distribution is observed by confocal microscopy. A good agreement is found between the experimental result and the numerical expectations. The experimental results highlight important effects of the electric field on the liquid distribution inside an FPHP, which could be ultimately used to enhance its thermal performance.