Experimental investigation of a dielectric liquid-vapor interface between two vertical planar electrodes: Influence of the DC electric field and temperature

•Observations of a liquid-vapor interface between vertical electrodes were performed.•The dielectrophoretic force controls both the position and the shape of the meniscus.•Free charges in the liquid could affect the interface behavior. The effect of a DC electric field on a liquid-vapor interface was investigated at different temperatures using a Pellat-like test cell filled with HFE-7000 and HFE-7100 dielectric fluids. Special attention was given to the local observations of the meniscus as this information is crucial in two-phase heat transfer applications. The results confirmed first that the dielectrophoretic force controls both the mean position and the shape of the meniscus as the visualizations revealed that the interface could be totally flattened when the electric field increased. The visualizations showed secondly that free charges in the liquid could affect the interface behavior in two ways: by slightly modifying the pressure profile in the liquid bulk, and by leading the formation of electrojets close to the wall. The temperature dependence of the vapor dielectric strength led to a drastic limitation at low temperature of the maximum electric field that the fluid could withstand before breakdown. This point should be carefully considered in electrohydrodynamics enhanced two-phase cooling systems.