Effect of Plasma Actuation on Impact, Dynamics, and Evaporation of Water Droplet on a Frozen Surface

In recent years, the plasma flow control team of Northwestern Polytechnical University has proposed and developed an anti-/de-icing method based on AC-SDBD plasma actuation. Further research found that the primary mechanisms are coupling aerodynamic and thermal effects. AC-SDBD plasma actuation produces many coupling effects, such as electromagnetic, aerodynamic, thermal, and chemical effects, etc. The role of these effects in the anti-icing/deicing process is still unclear. Therefore, more in-depth and detailed explorations are needed for the mechanism of plasma anti-/de-icing. This study experimentally studied the effects of AC-SDBD plasma actuation on the water droplet's impact, dynamics, and evaporation on a frozen surface of a flat plate. A high-speed imaging and the surface infrared temperature measurement were used to record the dynamic process of a water droplet impacting the frozen flat-plate surface with and without plasma actuation. The results showed that the different freezing temperature of the model surface has an obvious effect on the dynamic process of spreading, oscillation, and the final ice shape of the droplet. The icing process starts at the bottom of the droplet. With the decrease of the wall surface temperature, the temperature difference between the droplet and the model surface gets bigger, the underlying liquid droplet freezes faster, and the freezing phase change time gets shorter. When the plasma actuator is activating, it can effectively prevent the droplet from freezing, and it has an obvious effect on the spreading and oscillation process of the droplet. The water drop is pushed downstream and oscillates with the unsteady-on plasma actuation, and eventually evaporated.