Numerical Investigation of the Effect of Airfoil Camber on the Aerodynamic Performance of Small-Scale Horizontal Axis Wind Turbines

Öz

The aerodynamic performance of wind turbine rotors strongly depends on the characteristics of the selected airfoil profile and rotor configuration, particularly under low Reynolds number conditions typical of small-scale wind energy systems. In this study, the influence of airfoil camber and blade number on the aerodynamic performance of a horizontal axis wind turbine (HAWT) was investigated. Three airfoil profiles belonging to the NACA four-digit series, namely NACA 2412, NACA 4412, and NACA 6412, were analyzed using the QBlade software, which combines the XFOIL solver for airfoil analysis with the BEM method for rotor performance prediction. The aerodynamic characteristics of the airfoils were first evaluated in terms of lift coefficient (CL), drag coefficient (CD), and lift-to-drag ratio (CL/CD) over a Reynolds number range of 8×10⁴–2.5×10⁵, representing low wind speed conditions typical of regions such as Eastern Anatolia. Subsequently, rotor performance was investigated for two-, three-, and four-bladed configurations using power coefficient (Cₚ) and thrust coefficient (Ct) analyses. The results indicate that increasing airfoil camber enhances lift generation and aerodynamic efficiency. Among the investigated profiles, NACA 6412 achieved the highest Cₚ values, indicating improved energy extraction capability. However, this airfoil also generated higher thrust loads. Considering both power coefficient and thrust coefficient together, the NACA 4412 airfoil provided the most balanced aerodynamic performance. The results demonstrate that moderate camber airfoils can offer an effective compromise between energy production and aerodynamic loading for small-scale wind turbines operating under low Reynolds number conditions.

Anahtar Kelimeler

• Horizontal axis wind turbine
• BEM theory
• Low Re aerodynamics
• Rotor performance

Küçük Ölçekli Yatay Eksenli Rüzgâr Türbinlerinin Aerodinamik Performansı Üzerindeki Kanat Profili Kamburluğunun Etkisinin Sayısal Olarak İncelenmesi

Öz

Rüzgâr türbini rotorlarının aerodinamik performansı, özellikle küçük ölçekli rüzgâr enerjisi sistemlerinde tipik olan düşük Reynolds sayısı koşullarında, seçilen kanat profili ve rotor konfigürasyonunun özelliklerine büyük ölçüde bağlıdır. Bu çalışmada, yatay eksenli bir rüzgâr türbininin (HAWT) aerodinamik performansı üzerindeki kanat profili kavisinin ve kanat sayısının etkisi araştırılmıştır. Kanat profili analizi için XFOIL çözücüsünü, rotor performansı tahmininde ise BEM yöntemini birleştiren QBlade yazılımı kullanılarak, NACA dört haneli serisine ait üç kanat profili (NACA 2412, NACA 4412 ve NACA 6412) analiz edilmiştir. Kanat profillerinin aerodinamik özellikleri ilk olarak, Doğu Anadolu gibi bölgelere özgü düşük rüzgâr hızı koşullarını temsil eden 8×10⁴–2.5×10⁵ Reynolds sayısı aralığında kaldırma katsayısı (CL), sürükleme katsayısı (CD) ve kaldırma/sürükleme oranı (CL/CD) açısından değerlendirilmiştir. Daha sonra, güç katsayısı (Cₚ) ve itme katsayısı (Ct) analizleri kullanılarak iki, üç ve dört kanatlı konfigürasyonlar için rotor performansı incelenmiştir. Sonuçlar, kanat profili kavisinin artmasının kaldırma üretimini ve aerodinamik verimliliği artırdığını göstermektedir. İncelenen profiller arasında, NACA 6412 en yüksek Cₚ değerlerine ulaşarak enerji çıkarma kapasitesini iyileştirmiştir. Bununla birlikte, bu kanat profili daha yüksek itme yükleri de üretmiştir. Hem güç katsayısı hem de itme katsayısı birlikte değerlendirildiğinde, NACA 4412 kanat profili en dengeli aerodinamik performansı sağlamıştır. Sonuçlar, orta derecede kavisli kanat profillerinin, düşük Reynolds sayısı koşullarında çalışan küçük ölçekli rüzgâr türbinleri için enerji üretimi ve aerodinamik yükleme arasında etkili bir denge sağlayabileceğini göstermektedir.

Anahtar Kelimeler

• Yatay eksenli rüzgâr türbini
• BEM teorisi
• Düşük Re aerodinamiği
• Rotor performansı

Kaynakça

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