Ice heating measurement by laser-induced fluorescence during the de-icing of a droplet using surface dielectric barrier discharge

This study explores the melting dynamics of frozen water droplets exposed to a non-thermal Surface Dielectric Barrier Discharge (SDBD) plasma actuator, in the context of developing an active ice protection system. Unlike mechanical actuators, which are relatively energy-efficient but lack robustness, or resistive heaters, which are compact but highly energy-consuming, DBD plasma actuators offer a promising alternative by combining heat generation with reduced size and weight. A key focus is placed on measuring the temperature within the ice using a laser-induced fluorescence (LIF) technique. For this purpose, pyranine dye mixed with sucrose was used, enabling a highly temperature-sensitive fluorescence signal in the solid phase. However, the method becomes ineffective once melting progresses due to the limited emission of the deprotonated form of pyranine in liquid water. Melting of a 2-mm droplet was achieved 22–139 s after discharge activation, depending on operating parameters and dielectric material, with ice temperature rises between 3 and 20 °C. To detect the onset of melting, the discharge current was analyzed, with a notable decrease in the number of micro-discharge peaks observed as a liquid layer forms. Finally, by comparing the electrical power dissipated by the actuator with the thermal energy required to raise the droplet’s temperature to the onset of melting, the efficiency of the SDBD system could be evaluated at 0.1%. Results highlight the dominant role of dielectric heating and provide insight into the limitations and potential of plasma-based de-icing strategies.