Experimental Investigation of Surface Roughness Effect over Wind Turbine Airfoil

Öz

The present study ensures an experimental investigation of NACA4412 wind turbine blade airfoil prepared with the sandpaper as a roughness device in order to control its flow. The smoke-wire and hot-wire experiments were carried out at low Reynolds number ranging from 25000 to 75000 and angle of attack of 8°. As geometrical parameters, height of sandpaper and it location over the airfoil were conducted. It was positioned 15%-25% chord length. Height of sandpaper was selected 0.5 mm. The experimental results revealed that the flow over NACA4412 was affected when sandpaper was utilized because either amount of lift apparently increased or the location and size of laminar separation bubble (LSB) were changed. As a result, it was shown that the use of sandpaper provided passive flow control and it was an effective way in terms of delay or suppress separation over NACA4412 airfoil.

Anahtar Kelimeler

• Low reynolds number,Laminar separation bubble,Surface roughness,Passive flow control

Rüzgar Türbini Kanadı Üzerindeki Yüzey Pürüzlülüğü Etkisinin Deneysel İncelenmesi

Öz

Mevcut çalışma, akış kontrolü sağlamak için pürüzlülük elemanı olan zımpara kağıdı ile hazırlanmış NACA4412 rüzgar türbini kanadının deneysel çalışmasını sağlamaktadır. Duman teli ve Sıcak-tel anemometresi deneyleri 8° hücum açısında ve 25000 ile 75000 arasında değişen hücum açılarında gerçekleştirilmiştir. Geometrik parametre olarak, kanat üzerindeki pürüzlülüğün yeri ve yüksekliği ele alınmıştır. Pürüzlülük %15-25 kord boyuna yerleştirilmiştir. Zımpara kağıdı yüksekliği 0,5 mm olarak seçilmiştir. Önceden deneysel çalışmalar NACA4412 kanat profilinin aerodinamik performansı açısından iyi sonuçlar gösterecek mi şeklinde düşünülmüştü. Gerçekten, deneysel sonuçlar zımpara kağıdı kullanıldığı zaman NACA4412 kanat profili üzerindeki akışın etkilendiğini ortaya çıkardı, çünkü ya kanadın kaldırma miktarında belli bir artış vardı ya da laminer ayrılma kabarcığının konumu değiştirilmişti. Sonuç olarak, zımparanın kullanılması pasif akış kontrolü sağladığını ve NACA4412 kanat profili üzerindeki akış ayrılmasını ertelediği ya da yok ettiğini göstermektedir.

Anahtar Kelimeler

• Düşük reynolds sayısı,Laminer ayrılma kabarcığı,Yüzey pürüzlülüğü,Pasif akış kontrolü

Kaynakça

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