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Search Completed | Title | Experimental Study of Deicing and Anti-icing on a Cylinder by DBD Plasma Actuation
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Text | Experimental Study of Deicing and Anti-icing on a Cylinder by DBD Plasma Actuation | 002
stoppage by either icing up the carburetor or, in the case of a fuel-injected engine, blocking the engines air source.2
Supercooled water droplets are classified into two categories depending on their mean volumetric diameter. Supercooled small droplets have mean volumetric diameter between 10 μm to 50 μm and due to their lower mass they will follow the streamlines of the flow, which may lead to the droplets avoiding impact with the aircraft surface. Supercooled large droplets with mean volumetric diameter exceeding 50 μm (could go as high as few millimeters) are more dangerous for ice accretion.3
Mainly three types of structural ice are encountered during flight described as rime, clear (sometimes called glaze), or mixed. Formation of ice structure depends on the freestream temperature, droplet size and liquid water content.
A glaze ice formation is more likely to occur in cumuliform clouds at temperatures between 0 ◦C and -10 ◦C. The glaze ice formation occurs as the portion of the impinged droplet in contact with the surface freezes instantly but the rest of the droplet remain in liquid form due to the insufficient heat transfer and may flow back or run back. It is very cohesive and dense and hence harder to break off. A rime ice is formed in extremely cold freestream temperatures (usually for air temperatures below -10 ◦C) with moderate amount of liquid water content and smaller mean volumetric diameter. The droplets freeze immediately on contact with the airframe with no run back. Since the rime ice takes the shape of the airframe structure, this type of ice induces less aerodynamic penalties than glaze ice even with added thickness and roughness (compared to a clean airfoil). A combination of rime and glaze ice is usually formed since various types and degrees of icing conditions may be encountered throughout the flight of an aircraft.3,4
To minimize the performance penalties due to icing conditions, numerous methods have been proposed and used for the protection of aircraft in icing conditions, which must comply with flight safety regulations outlined by national certification authorities such as the FAA (Federal Aviation Administration), the EASA (European Aviation Safety Agency) and Transport Canada, or other governmental entities.
These methods fall into two distinct categories based: 1) deicing or ice removal, and 2) anti-icing or ice prevention. The first type prevents the formation of ice completely from the protected areas, while the later removes it after a certain amount is accumulated. In general, they can also be classified into three categories:5, 6
1) liquid-based, such as weeping wings.
2) mechanical-based, such as pneumatic boots.
3) thermal-based, such as hot-air7, 8 and electro-thermal systems.5
On most large, turbine powered aircraft, hot air from the engines is routed through piping in the wings,
tail and engine openings to heat their surfaces and prevent icing. On propeller driven aircraft, balloon-like devices attached to the wings and tail are inflated and deflated with air from the engines, breaking up any ice accumulation.
The current work employs experimental study to examine a new method of icing control using the plasma actuation. Plasma active flow control has received growing attention in recent 10 years because of the advantages of not having mechanical parts, zero reaction time, broader frequency bandwidths and relatively low energy consumption. What is most important, the plasma actuators can be arranged conveniently on the parts surface of the vehicle. Corke et al,9 Moreau,10 Little et al.,11 Yun Wu and Yinghong Li,12 Jinjun Wang et al.,13 Zhenbing Luo et al.14 give an overview of the various technologies used and highlight the potential of such actuators. To generate such a discharge, a high voltage is applied between two copper electrodes asymmetrically placed on either side of a dielectric material. One such development is the use of dielectric barrier discharge (DBD) plasma actuators driven by Alternating Current (AC-) source. The effect of the AC-DBD actuator is to impart momentum to the flow, much like flow suction or blowing but without the mass injection.
The plasma can heat the electrode sheet, the substrate and the surrounding air, there have a number of studies noticing on the temperature effect for the DBD actuators.15–21 Joussot et al.15 investigated thermal effect associated with the AC-DBD plasma actuation. The surface temperature of the dielectric was measured by infrared thermal imaging in quiescent air and in wind tunnel with 20 m/s wind speed while a DBD actuator was continuously running. Measurements showed a fast and significant linear increase in the dielectric temperature at the ignition of the discharge on the order of 50 ◦C. A heat dissipation resulting in a drop in the dielectric temperature was observed in wind tunnel test. Stanfield et al.16 obtained the spatially resolved rotational and vibrational temperatures for a dielectric barrier discharge (DBD) using emission spectroscopy. The results shown that the maximum rotational temperature in the DBD was 137 ◦C located
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American Institute of Aeronautics and Astronautics
Downloaded by NORTHWESTERN POLYTECHICAL UNIV. on June 23, 2016 | http://arc.aiaa.org | DOI: 10.2514/6.2016-4019
Image | Experimental Study of Deicing and Anti-icing on a Cylinder by DBD Plasma Actuation
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