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... They studied and analyzed several different operational parameters and demonstrated that these actuators allow to significantly increase the lift coefficient of turbine blades and, consequently, may allow to harvest about 10% more energy at low wind speeds. Besides the possibility of applying micro plasma actuators for flow control, Lindner et al. (2020) demonstrated that these actuators can also be used to perform ice mitigation operations. ...
Chapter
During the last twenty years dielectric barrier discharge (DBD) plasma actuators have been a topic of interest for flow control and aeronautic applications. They present several advantages such as lightweight, low cost, fast response time and can be easily controlled by simple electronic means. Besides the flow control applications, during the recent years several authors have also proven the ability of plasma actuators for performing simultaneously boundary layer flow control and deicing or anti-icing operations. However, the conventional DBD plasma actuator configuration has shown some weaknesses related to its aerodynamic efficiency and durability. Due to that, during the recent years several authors have developed different DBD plasma actuator configurations with the ambition of improving the induced flow velocity field and/or the durability. Furthermore, new plasma actuator (PA) configurations have been also developed in order to obtain a better actuator efficiency for specific applications. Micro-PA, Nano second PA, Plasma Synthetic Jet Actuator (PSJA), Curved PA, Multiple Encapsulated Electrodes PA, sliding discharge PA, stair-shaped PA and segmented encapsulated * Corresponding Author's Email: fmfr@ubi.pt. Frederico Rodrigues and Jose Pascoa 2 electrodes PA are examples of innovative dielectric barrier discharge plasma actuator configurations that were reported in the literature and which present several different advantages when compared with the conventional one. However, till now, there are no works in the literature explaining the differences between all of these new plasma actuator configurations and discussing which ones are more suitable for each type of application. Considering this background, the current work aims to review all the new plasma actuators configurations and compare the advantages and disadvantages of each configuration for different applications.
... Whereas the related topic of plasma actuators (PA) for flow control applications is widely studied [9][10][11][12][13][14][15][16][17][18][19][20], there is recently a growing interest in the study of surface dielectric barrier discharges (SDBDs) as an anti-icing and de-icing system [21][22][23][24][25][26][27][28][29][30]. Probably Meng et al. [24] and Cai Jinsheng et al. [21] were the first who reported experimental results indicating that SDBDs can work as an anti/de-icing system. ...
Article
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Avoiding ice accumulation on aerodynamic components is of enormous importance to flight safety. Novel approaches utilizing surface dielectric barrier discharges (SDBDs) are expected to be more efficient and effective than conventional solutions for preventing ice accretion on aerodynamic components. In this work, the realization of SDBDs based on thin-film substrates by means of micro-electro-mechanical-systems (MEMS) technology is presented. The anti-icing performance of the MEMS SDBDs is presented and compared to SDBDs manufactured by printed circuit board (PCB) technology. It was observed that the 35 μm thick electrodes of the PCB SDBDs favor surface icing with an initial accumulation of supercooled water droplets at the electrode impact edges. This effect was not observed for 0.3 μm thick MEMS-fabricated electrodes indicating a clear advantage for MEMS-technology SDBDs for anti-icing applications. Titanium was identified as the most suitable material for MEMS electrodes. In addition, an optimization of the MEMS-SDBDs with respect to the dielectric materials as well as SDBD design is discussed.
Article
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The application of innovative technologies in aerospace, such as the laminar flow control, composite materials, and fully electric propulsion, brings new challenges to traditional anti-/de-icing methods in recent years. The new concept of anti-/de-icing based on high voltage driven surface dielectric barrier discharge (SDBD) plasma actuators which have no complicated mechanical structures nor potential aerodynamic loss, has the great potential to be applied to the next-generation flight vehicle. The present study reviews the anti-/de-icing technique using SDBD plasma actuators from three aspects, i.e. in-flight icing mechanism and available anti-/ de-icing approaches, characteristics of the plasma aerodynamics and the thermal actuation effect, and anti-/ de-icing applications using SDBD plasma actuators. It is pointed out that the key scientific issues in the research of anti-/de-icing using plasma actuators mainly include the following: 1) multi-physics coupling mechanism, especially the plasma aerodynamics and thermal actuation effect as the two main factors; 2) evolution and mechanism of non-equilibrium phase transition of multi-physics during the anti-/de-icing process. Those scientific issues include many frontier areas in fluid mechanics, such as the physical properties of plasma, flow control mechanism, in-flight icing mechanism, and anti-/de-icing rules. The difficulty of the research of plasma anti-/de-icing lies in the coupling of multiple physical fields and multiple time scales. Numerical simulation
Article
Developing the fundamentals for the electrical diagnostics of surface dielectric barrier discharges (SDBDs) is of enormous importance for several applications, for example, flow control and gas cleaning. The main challenge is to account for the discharge expansion along the dielectric surface. Typically, a linear expansion with the amplitude of the applied voltage is observed. In this work, we report on a step-wise SDBD expansion along the Al 2 O 3 dielectric surface. More specific, the discharge occupied a certain area after ignition, which remained constant until the voltage exceeded the critical amplitude V L . This absence of expansion is seen as a linear dependence of the discharge power on the applied voltage and it was additionally confirmed by photographs with long exposure times. This novel phenomenon is more pronounced for thicker dielectrics. It is suggested that the derivative of the charge-voltage characteristics can be used for the determination of all essential parameters of the simplest equivalent circuit of SDBDs. Moreover, it was shown that the derivative of the charge-voltage characteristics for the positive half-cycle of the discharge agrees numerically with the voltage dependence of the reactor capacitance derived from photographs. This agreement between both measurement methods indicates a similar step-wise expansion of the SDBD even if a voltage amplitude above V L is applied.
Article
The mechanical-vibration-based de-icing method removes ice that has accumulated on an airfoil structure through the ultrasonic excitation of piezoelectric actuators, and it has considerable potential for use in aircraft anti-icing/de-icing technology. This study examines the problem of the bonding gap in flat-ended piezoelectric actuators when they are mounted on the curved surfaces of wings, and it determines the installable region for bonding of suitable quality for each actuator. The influence of the adhesive layer on interfacial shear stress and the thickness threshold are first obtained by using a finite element simulation that considers the adhesive layer. We then discuss algorithms to determine the installable region for three research objects—two-dimensional curves of the airfoil, two-dimensional plane surfaces, and three-dimensional airfoil surfaces—and use them to calculate the suitable area for actuator adhesion with bonding gaps of a limited size. The influence of the parameters of wing structures, such as the wing rib and positions of other sensors, is also considered. The accuracy of the algorithms is verified by analyzing cases involving actuators of difference sizes and surfaces. The usefulness of determining the characteristics of the leading edges of airfoils of different shapes is also highlighted.
Article
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Anti-icing performance using the surface dielectric barrier discharge plasma actuator is studied using detailed visualization and surface thermal measurements. To reveal the physical mechanism of coupled aerodynamic and thermal effects on anti-icing, three types of actuators are designed and mounted on a NACA 0012 airfoil. The coupled aerodynamic and thermal effects are confirmed in still air. The results show that the plasma actuation is effective for in-flight anti-icing, and the anti-icing performance is directly related to the design of the plasma actuators based on the coupled aerodynamic and thermal effects. When the direction of plasma induced flow is consistent with the incoming flow, the heat generated by plasma discharge is concentrated in the region of the actuator and the ability of the actuator for heat transfer downstream is relatively weak during the anti-icing. When the induced flow is opposite to the incoming flow, there is less heat accumulation in the actuator region, while the ability of heat transfer downstream becomes stronger. With the consistent and opposite direction of induced flow, the plasma actuation can ensure that 57% and 81% chord of the lower surface of the airfoil are free of the ice accumulation, respectively. Another actuator is designed to induce the air jets approximately perpendicular to the airfoil surface. This exhibits both a stronger ability of heat accumulation locally and heat transfer downstream and hence ensures that there is no ice on the entire lower surface of the airfoil.
Article
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It is a known phenomenon that some dielectric materials used to construct plasma actuators degrade during operation. However, the rate at which this process occurs, to what extent, as well as a method to monitor is yet to be established. In this experimental study, it is shown that electrical measurements can be used to monitor changes in the material of the plasma actuators. The procedure we introduce for monitoring the actuators follows from the work of Kriegseis, Grundmann, and Tropea [Kriegseis et al., J. Appl. Phys. 110, 013305 (2011)], who used Lissajous figures to measure actuator power consumption and capacitance. In the present study, we quantify changes in both the power consumption and capacitance of the actuators over long operating durations. It is shown that the increase in the effective capacitance of the actuator is related to degradation (thinning) of the dielectric layer, which is accompanied by an increase in actuator power consumption. For actuators constructed from layers of Kapton® polyimide tape, these changes are self-limiting. Although the polyimide film degrades relatively quickly, the underlying adhesive layer appears to remain intact. Over time, the effective capacitance was found to increase by up to 36%, 25%, and 11% for actuators constructed with 2, 3, and 4 layers of Kapton tape, respectively. A method is presented to prevent erosion of the Kapton dielectric layer using a coating of Polydimethylsiloxane oil. It is shown the application of this treatment can delay the onset of degradation of the Kapton dielectric material
Article
A numerical simulation of the anti-icing of aircraft surfaces is presented. The simulation utilizes the breakup of a uniformly thin liquid film into individual streams or rivulets separated by dry spaces to more accurately describe the physics of runback water. A two-dimensional heat transfer approach is used to calculate the temperature distribution in the runback water and in the solid wall. The model allows a multilayer representation of the solid wall with the possibility of heating the surface by means of electrical heating elements embedded within the layers or by means of convective heating of the surface from the inside using compressor bleed air. Parametric studies are performed to investigate the effects of some of the problems variable on the results.
Article
Studies have been made of ice formed by accretion over a wide range of controlled conditions to ascertain the influence of the wind speed, ambient temperature, droplet diameter and liquid-water concentration in the supercooled cloud, and the size of the accreting object. The density of the deposits ranged from 0·1 to 0·9 g cm−3, the density increasing with increases in the first four of the above parameters but decreasing with increasing object size. It was found that the density could be expressed as a function of − rv0/Ts, r being the median volume radius of the droplets comprising the cloud, v0 the speed with which the droplets struck the object and Ts the mean temperature of the accreting surface (in °C). The quantity rv0 is interpreted as being a measure of the force with which the droplets were packed together and Ts the temperature which governed their freezing rate. A microscopic examination of the deposits showed that at low values of − rv0/Ts (corresponding to low densities) the droplets tended to freeze together as spheres while at higher values they were distorted and spread considerably before freezing.
Full-Scale Runback Ice: Accretion and Aerodynamic Study
  • Alegre Nathalie
Nathalie ALEGRE, 2010. Full-Scale Runback Ice: Accretion and Aerodynamic Study, PhD THESIS
Implementation and calibration of the icing and contamination research facility (iCORE)
  • T Hauk
  • T Strobl
  • D Raps
Hauk, T., T. Strobl, and D. Raps. "Implementation and calibration of the icing and contamination research facility (iCORE)." ILASS-Europe, 25th European Conf. on Liquid Atomization and Spray Systems, Chania, Greece. Vol. 1. No. 4. 2013.