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Abstract(s)
Os actuadores a plasma de barreira dieléctrica de descarga (DBD) são dispositivos
bastante atractivos para as indústrias aeronáutica e eólica, principalmente para
aplicações que envolvem controlo de escoamento e degelo. Tendo em conta a escassez de
métodos experimentais para análise das características térmicas dos actuadores a
plasma, pretendeu-se com esta dissertação construir um sistema Schlieren orientado
para o fundo que permita analisar o campo de temperaturas do escoamento induzido por
actuadores a plasma. Ao longo da dissertação este sistema e todo o método quantitativo
por detrás dele vão ser elaborados e optimizados de forma a obter uma correcta
calibração e validação deste sistema. Primeiramente, o sistema Schlieren orientado para
o fundo (BOS) foi construído e calibrado através de informação presente na literatura e
da realização de ensaios de optimização. Posteriormente, foram feitas análises a vários
objectos de fase gerados por uma vela, uma placa de aquecimento e um maçarico de
cozinha. As temperaturas do escoamento originado pela convecção do calor gerado por
estes diferentes objectos foram quantificadas, recorrendo ao sistema BOS, e validadas
com recurso a um termopar. Após a validação da técnica BOS, actuadores a plasma com
diferentes espessuras e diferentes camadas dieléctricas foram fabricados.
Primeiramente, estes actuadores foram caracterizados electricamente e foi quantificada
a velocidade de escoamento induzido. Depois, foi então aplicada a técnica BOS
desenvolvida para análise do campo de densidades e de temperaturas. Neste estudo,
concluiu-se que a técnica BOS é um método experimental não-intrusivo que permite
quantificar as temperaturas do escoamento induzido por actuadores a plasma com
precisão. Para além disso, verificou-se que os actuadores a plasma permitem aumentar
significativamente a temperatura do ar adjacente, o que lhes confere um elevado
potencial para aplicações de degelo e prevenção de acumulação de gelo.
Dielectric Barrier Discharge (DBD) plasma actuators are very attractive devices for aeronautical and wind power industries, mainly when we consider applications that require flow control and deicing. Considering the lack of experimental techniques for plasma actuators thermal characteristics analysis, the aim of this dissertation consisted on building a background oriented Schlieren system to analyse the temperature field of plasma actuators’ induced flow. Throughout the dissertation, this system and the analytical method behind are elaborated and optimized in order to obtain an appropriate calibration and validation. First, the background oriented Schlieren system was constructed and calibrated by using the information reported in the literature and by performing several optimization experiments. Afterwards, analyses were performed on several phase objects provided by a candle, a hotplate and a kitchen blowtorch. The temperatures of the convective flow provided by these objects were quantified by using the BOS system and validated with thermocouple measurements. After the BOS system validation, plasma actuators with different thicknesses and different dielectric materials were fabricated. Initially, these actuators were electrically characterized and the induced flow velocity was quantified. After that, the developed BOS technique was applied for density and temperature field analysis. In the current study, it was concluded that the BOS technique is a non-intrusive experimental method which accurately allows to quantify the plasma actuators induced flow temperatures. Besides that, it was verified that the plasma actuators allow to significant increase the adjacent air temperature, making them suitable for deicing and ice accumulation prevention applications.
Dielectric Barrier Discharge (DBD) plasma actuators are very attractive devices for aeronautical and wind power industries, mainly when we consider applications that require flow control and deicing. Considering the lack of experimental techniques for plasma actuators thermal characteristics analysis, the aim of this dissertation consisted on building a background oriented Schlieren system to analyse the temperature field of plasma actuators’ induced flow. Throughout the dissertation, this system and the analytical method behind are elaborated and optimized in order to obtain an appropriate calibration and validation. First, the background oriented Schlieren system was constructed and calibrated by using the information reported in the literature and by performing several optimization experiments. Afterwards, analyses were performed on several phase objects provided by a candle, a hotplate and a kitchen blowtorch. The temperatures of the convective flow provided by these objects were quantified by using the BOS system and validated with thermocouple measurements. After the BOS system validation, plasma actuators with different thicknesses and different dielectric materials were fabricated. Initially, these actuators were electrically characterized and the induced flow velocity was quantified. After that, the developed BOS technique was applied for density and temperature field analysis. In the current study, it was concluded that the BOS technique is a non-intrusive experimental method which accurately allows to quantify the plasma actuators induced flow temperatures. Besides that, it was verified that the plasma actuators allow to significant increase the adjacent air temperature, making them suitable for deicing and ice accumulation prevention applications.
Description
Keywords
Actuadores a Plasma Análise
Quantitativa Análise de Escoamentos Dbd Schlieren Orientado para o Fundo