Session: 06-01-01: General Aerospace-1

Paper Number: 166163

Investigation of the Dielectric Barrier Discharge Plasma Actuators Degradation in High Temperature Environments 

Surface dielectric barrier discharge plasma actuators (SDBD) are vital in aerodynamic flow control and drag reduction. From a practical perspective, SDBDs enable airflow control through electrokinetic conversion mechanisms known, in the scientific community, as electrohydrodynamic (EHD) force. Owing to their thermal power loss, SDBD plasma actuators have also been proposed as ice sensing and anti-/de-icing devices. Consequently, since they can fulfill several functions – to exploit them fully – a dielectric material capable of withstanding prolonged exposure to plasma generation is required.

Six SDBD plasma actuators with 1 mm thick dielectrics made of Kapton®, Teflon®, and polyisobutylene (PIB) were analyzed under room- (25 ºC) and high-temperature (150 ºC) environment regimes. Specifically, four cycles of 2.5 hours per actuator were conducted until achieving a total of 10 hours. Electrical parameters, including power consumption, capacitance, and maximum charge were recorded throughout the degradation tests to study their modifications. Fourier transform infrared (FTIR) spectroscopy in the plasma discharge region was analyzed to assess the molecular modification of the polymers induced by prolonged plasma discharge phenomena. Additionally, different surface roughness parameters were measured and analyzed. Considering the chemical compositions and the thermal properties of the three polymeric dielectrics, thermogravimetric analysis was performed to provide insights into the thermal degradation effect caused by plasma discharge.

Preliminary results showed that, at room temperature, PIB- and Teflon®-based plasma actuators ruptured in less than 4 h (under 240 minutes), whilst the Kapton® actuator performed over the entire time range established, i.e., 10 h. At 150 ºC, Kapton®-based DBD plasma actuator endured both long-exposure plasma discharge phenomena and high-temperature environment degradations without failing by arc before completing the 10 h test. On the other hand, Teflon® and PIB actuators suffered total degradation at 140 minutes, and 200 minutes, respectively. Curiously, at high temperatures, PIB dielectric showed an 80 minute longer lifetime since it ruptured at 200 minutes, while at room temperature, it failed at 120 minutes. After normalizing by the first measurement, the average power consumption of the Kapton® and Teflon® actuators showed little oscillation compared to the average power consumption evolution at high temperatures. The standard deviation for the average power consumption that Kapton® and Teflon® plasma actuators presented at 25 ºC were 0.32, and 0.06, respectively, while at 150 ºC the values increased to 0.59, and 0.38. Once again, PIB-based actuators contradicted other materials' behavior by having a lower standard deviation of 0.16 at 150 ºC and 0.18 at room temperature. Additionally, the time evolution of average maximum charge and average capacitance were considered synchronous between them, and with the power consumptions, evincing, therefore, good agreement of electrical parameters. The degradation characteristics of the six DBD plasma actuators were captured using a digital microscope. The images revealed burned, damaged, and detachment areas on and among the electrode and the dielectric layer.

Lastly, as expected, regardless of the dielectric material, all actuators, i.e., the virgin and the aged ones, presented an average roughness, lower than the root mean square roughness. Both parameters were always lower for the virgin plasma actuators than for the aged ones at room or high temperatures. FTIR spectroscopy and thermogravimetric analysis are expected to clarify the reasons behind the different behavior observed in PIB compared to Kapton®- and Teflon®-based actuators.

Presenting Author: Kateryna Oleksandrivna Shvydyuk University of Beira Interior

Presenting Author Biography: Kateryna Shvydyuk has received an integrated master's degree in Aeronautical Engineering from the University of Beira Interior. She participated in complementary courses (ESA Academy) and competitions (ActInSpace Hackaton and Coimbra Space Summer School) during her studies. She is the winner of the First Honorable Mention in the Best Thesis Award 2023 competition in the Materials Science field in Portugal. While finishing her master's and being a Visiting Researcher at the Centre for Aerospace Science and Technologies (C-MAST), she worked as a Systems Engineer for the aerospace and naval defense-related industries. Nowadays, she is a PhD candidate in Mechanical Engineering.

Authors:

Kateryna Oleksandrivna Shvydyuk University of Beira Interior
Frederico Miguel Freire Rodrigues University of Beira Interior
Abílio Pereira Silva University of Beira Interior