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Search Completed | Title | Optimization of Dielectric Barrier Discharge Plasma Actuators for Icing Control
Original File Name Searched: 2020-Haiyang-Plasma-J-Aircarft.pdf | Google It | Yahoo | Bing
Text | Optimization of Dielectric Barrier Discharge Plasma Actuators for Icing Control | 002
384 J. AIRCRAFT, VOL. 57, NO. 2:
Inspired by the aforementioned advantages, the plasma icing control studies are experiencing rapid development. Zhou et al.  conducted the study over an airfoil model using SDBD plasma generation for icing mitigation. The results demonstrated that SDBD plasma actuators could be used as a promising anti-icing tool for aircraft by taking advantage of the thermal effects associated with plasma generation. Tian et al.  showed an effective icing control using a pulsed dielectric barrier discharge plasma actuation with a freestream velocity of 90 m/s, which exhibited the compatibility of SDBD plasma actuation in preventing aircraft icing in flight for real applications. Liu et al.  revealed that the AC-SDBD plasma actuators have a great potential for more efficient anti-/deicing oper- ations on aircraft in comparison with the conventional electrothermal methods.
Furthermore, Meng et al.’s  research showed that the coupling between plasma-induced flow and thermal effects of the discharge form the fundamental mechanism for the icing control of AC-SDBD plasma actuation. For optimization of the actuators, both the dis- charge heat and the induced aerodynamic effects of the plasma actuation must be considered.
In most icing control studies, the design and placement of the actuator are directly used as the parameters in the flow control studies; i.e., the actuators were attached mostly around a separation point on the upper surface of the airfoil . As a result, the optimization of an AC-SDBD plasma actuator for the anti-/de-icing study is necessary. In the present research, both the original design of the plasma actuator based on flow control and the optimized design of the actuator for anti-icing are validated experimentally on a realistic configuration of the NACA0012 airfoil model. The criterion for actuator optimization is to elevate the ability of anti-icing, i.e., to ensure that most of the airfoil is free of ice accretion. The surface temperature distribution and ice accretion images are used to observe the anti-icing effects in detail.
and b) plasma actuators mounted on the upper surface of the airfoil model.
For the single AC-SDBD plasma actuator, a near-wall jet toward the encapsulated electrode is generated. As shown in previous results , the induced airflow in this study is perpendicular to the surface of the model due to the interaction of the airflow generated by the adjacent actuators. Such normal flow would enhance the mixing effect between the thermal energy produced by plasma and the cold boundary layer, which will enhance the anti-/deicing efficiency.
During the icing experiment, the starboard-side actuator was always kept off, whereas the portside actuator was turned on for icing control. The anti-icing performance over the airfoil surface for the plasma-on side (i.e., port side) would be compared side by side against that on the plasma-off side (i.e., starboard side) to evaluate the effectiveness of the SDBD plasma actuator under identical icing conditions.
During the experiment, two different actuator configurations (original and optimized) were tested, see Fig. 2. In the case of original actuators inspired by the flow control application, the whole actuator only covered the upper surface and was located around the separation point at the stall angle of attack [33–35].
For the optimized configuration, the difference in comparison with the original one was that the leading edge of the airfoil was covered. The purpose of the optimization was to achieve as much heat accumulation as possible on the leading edge due to the locally low flow speed around the stagnation point. This accumulation of the heat as well as the transfer of it downstream with the incoming flow and the plasma-induced flow are very important for the anti-icing of the airfoil. Moreover, it will ensure less ice accretion probability on the airfoil surface.
The actuator was connected to a high-voltage ac source that could provide a peak-to-peak amplitude varying from 0 to 30 kV and center frequency from 5 to 15 kHz. The voltage applied to the actuator was measured by a Tektronix P6015A high-voltage probe. In this study, the voltage on the actuator was kept at 13 kV and the frequency was set at 10 kHz.
A high-speed imaging system, which was a Dimax model of PCO- Tech, Inc., with a 2000 × 2000 pixel maximum spatial resolution, along with a 60 mm optical lens (Nikon, 60 mm Nikkor 2.8D) was used to record the ice accretion process. An infrared thermal imaging system (model FLIR-A615) was used to map the corresponding temperature distributions (from the leading edge up to 70 % of chord length) over the surface of the airfoil model during the ice accretion
The anti-icing experiments were conducted in a closed-circuit low- speed icing research wind tunnel at the Aerospace Engineering Department of Iowa State University. The test section is 2.0 m long that is 0.4 m height × 0.4 m width in cross section.
All four sidewalls were made transparent to have optical access for the high-speed camera as well as Infra Red camera. The NACA0012 airfoil was chosen as the test model. The chord length of the airfoil was set at 0.15 m, and the spanwise distance was 0.4 m. The angle of attack was fixed at −5°C for all the test cases. Only the icing control over the leading edge and the upper surface was studied due to less ice accumulation over the lower surface and the limitation of the exper- imental setup.
In the present study, the freestream velocity was kept constant at U∝ 40 m∕s, and the surrounding air temperature was T∝ −10°C. The corresponding Reynolds number Re number was about 3.6 × 105 based on the chord of the airfoil in the airflow without water spray. The liquid water content (LWC) of the incoming airflow was 1.0 g∕m3 . For all the test cases, the icing wind tunnel was operated at a prescribed temperature level for about 20 min to ensure the test section reached the thermal equilibrium. Then, the SDBD plasma actuator was switched on for about 10 s before turning on the water spray system. The origin of the time was set at the beginning of the water spray. As the water spray system was switched on, the super- cooled water droplets carried by the incoming airflow would impinge onto the surface of the airfoil model.
A multi-SDBD plasma actuator (i.e., actuator consisting of several long single stripe actuators) was installed on the surface of the airfoil. The single SDBD actuator was composed of two 0.07-mm-thick copper electrodes, which were arranged asymmetrically. Three layers of Kapton tape (0.056 mm per layer) separated the two electrodes as the dielectric barrier layer; see Fig. 1a. There was no gap or overlap between the exposed and encapsulated electrodes to encourage uni- form plasma generation. As shown in Fig. 1b, two sets of multi-SDBD plasma actuators were embedded on the upper surface of the airfoil, symmetrically, to the middle span of the airfoil model.
Schematic illustrations of a) single SDBD plasma actuator design
Downloaded by IOWA STATE UNIVERSITY on June 29, 2020 | http://arc.aiaa.org | DOI: 10.2514/1.C035697
Image | Optimization of Dielectric Barrier Discharge Plasma Actuators for Icing Control
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