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Desenvolvimento e análise experimental de atuadores a plasma baseados em polímeros eletroativos para controlo ativo de escoamentos e mitigação de acumulação de gelo
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Authors
Abstract(s)
Os atuadores a plasma de barreira dielétrica de descarga (DBD) são dispositivos
eletrónicos com grande interesse nas áreas da indústria aeronáutica e eólica,
particularmente para aplicações de controlo de escoamento e degelo. A presente
dissertação tem como objetivo propor e estudar uma nova classe de atuadores a plasma
baseado em polímeros eletroativos (EAP). Este novo tipo de atuador, para além das
capacidades de um atuador a plasma convencional, apresenta ainda a capacidade de
geração de movimento da sua superfície dielétrica, através de ativação eletrostática, que
promove a remoção de gelo. Primeiramente, foi selecionado um elastómero dielétrico e
uma graxa condutora com características especificas para viabilizar o novo conceito de
atuador EAP. Estes materiais foram utilizados para fabricar atuadores a plasma e foi
demonstrado que permitem eficazmente gerar uma descarga de plasma semelhante à
gerada por atuadores convencionais. Posteriormente, o polímero eletroativo foi testado
com níveis de alta tensão DC e foi quantificada a percentagem de aumento de área da
superfície por ação das forças eletrostáticas. Seguidamente, foram construídos três
atuadores EAP com espessuras de camada dielétrica diferentes (1mm, 2mm e 3mm) e
foram analisados minuciosamente quanto ao seu comportamento elétrico,
comportamento fluido dinâmico e comportamento térmico. Estas análises foram
também realizadas para atuadores convencionais de Kapton, com a mesma definição
geométrica, de modo a comparar os resultados com um atuador a plasma DBD de
referência. Os resultados demonstraram que para níveis de tensão mais elevadas o
polímero pode atingir um aumento de cerca de 100% da sua área superficial. Para além
disso, foi demonstrado que o atuador EAP consegue gerar velocidades de escoamento
induzido superiores a 3 m/s, sendo por isso viável para funções de controlo de
escoamento. Por último, verificou-se que os atuadores EAP, à semelhança com atuadores
a plasma convencionais, proporcionam um aumento considerável da temperatura de
superfície, podendo atingir temperaturas superiores a 100 ºC.
Dielectric Barrier Discharge (DBD) plasma actuators are electronic devices of great interest in the aeronautical and wind power industries, particularly for flow control and deicing applications. This dissertation aims to propose and study a new class of plasma actuators based on electroactive polymers (EAP). In addition to the capabilities of a conventional plasma actuator, this new type of actuator also has the ability to generate movement on its dielectric surface through electrostatic activation, which promotes ice removal. Firstly, a dielectric elastomer and a conductive grease with specific characteristics were selected to make the new EAP actuator concept viable. These materials were used to manufacture plasma actuators and were shown to effectively generate a plasma discharge similar to that generated by conventional actuators. Subsequently, the electroactive polymer was tested at high DC voltage levels and the percentage increase in surface area due to electrostatic forces was quantified. Three EAP actuators with different dielectric layer thicknesses (1mm, 2mm, and 3mm) were then built and thoroughly analyzed in terms of electrical behavior, fluid dynamic behavior, and thermal behavior. These analyses were also carried out for conventional Kapton actuators, with the same geometric definition, in order to compare the results with a conventional DBD plasma actuator. The results showed that at higher voltage levels the polymer can achieve an increase of around 100% in its surface area. In addition, it was shown that the EAP actuator can generate induced flow velocities above 3 m/s, making it viable for flow control operations. Finally, it was found that EAP actuators, similarly to conventional plasma actuators, provide a considerable increase in surface temperature, reaching temperatures above 100 ºC.
Dielectric Barrier Discharge (DBD) plasma actuators are electronic devices of great interest in the aeronautical and wind power industries, particularly for flow control and deicing applications. This dissertation aims to propose and study a new class of plasma actuators based on electroactive polymers (EAP). In addition to the capabilities of a conventional plasma actuator, this new type of actuator also has the ability to generate movement on its dielectric surface through electrostatic activation, which promotes ice removal. Firstly, a dielectric elastomer and a conductive grease with specific characteristics were selected to make the new EAP actuator concept viable. These materials were used to manufacture plasma actuators and were shown to effectively generate a plasma discharge similar to that generated by conventional actuators. Subsequently, the electroactive polymer was tested at high DC voltage levels and the percentage increase in surface area due to electrostatic forces was quantified. Three EAP actuators with different dielectric layer thicknesses (1mm, 2mm, and 3mm) were then built and thoroughly analyzed in terms of electrical behavior, fluid dynamic behavior, and thermal behavior. These analyses were also carried out for conventional Kapton actuators, with the same geometric definition, in order to compare the results with a conventional DBD plasma actuator. The results showed that at higher voltage levels the polymer can achieve an increase of around 100% in its surface area. In addition, it was shown that the EAP actuator can generate induced flow velocities above 3 m/s, making it viable for flow control operations. Finally, it was found that EAP actuators, similarly to conventional plasma actuators, provide a considerable increase in surface temperature, reaching temperatures above 100 ºC.
Description
Keywords
Atuador a Plasma Controlo de Escoamento Degelo Polímeros Eletroativos