Characterization Of The Electrothermal Conversion Mechanisms Of A Plasma Actuator For Icing Control

Abstract

The characterization of a new icing protection system, specifically a dielectric barrier discharge (DBD) plasma actuator, is conducted in this study. The system operates by establishing an AC high voltage between two electrodes arranged on opposite sides of a dielectric material. This setup generates a plasma on the dielectric surface, which in turn induces a significant temperature rise (about 30°C) in both the dielectric surface and the surrounding air. To gain a comprehensive understanding of the electrothermal conversion mechanisms involved in the discharge, a Planar Laser Induced Fluorescence technique is employed. Using a two-colour one-dye ratiometric method (PLIF2c1d), the technique provides measurements of the temperature evolution of an ice droplet deposited on the actuator during its melting process by the discharge. An annular actuator configuration is chosen to minimise the effect of the generated ionic wind and maintain the droplet in the discharge. A pyranine and sucrose solution is identified and temperature calibrated. The calibration process involves depositing a droplet of the solution in a temperature-controlled enclosure capable of reaching temperatures as low as -22°C. Through detailed spectral analysis, two specific detection spectral bands are selected for the imaging applications. These bands enable measurements of the ice temperature with a sensitivity of 7.61%/°C. The effects of laser light scattering by ice and fluorescence reabsorption are also investigated by varying the ice thickness. They are found to have limited influence on the fluorescence emission when the solution in ice form. Finally, the capacity of the technique is evaluated by measuring the ice temperature evolution during the melting induced by a plasma discharge. Droplets are deposited on two dielectric materials, namely PTFE and Sapphire, which possess distinct thermal and dielectric properties. Comparisons under varying plasma discharge power levels provide valuable insights into the optimization of DBD plasma actuators for effective icing protection.