KEMAL KOCA, M. Serdar GENÇ, H. Hakan AÇIKEL

Experimental Investigation of Surface Roughness Effect over Wind Turbine Airfoil

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

RüzgarTürbini Kanadı Üzerindeki Yüzey Pürüzlülüğü Etkisinin Deneysel İncelenmesi

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 hotwire 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.

___

1.Hossain, M.S., Raiyan, M.F., Akanda, M.N.U., Jony, N.H.A.,A Comparative flow analysis of NACA 6409 and NACA 4412 aerofoil,International Jornal of Research in Engineering and Technology3.

2.Amanullah,C.,Arjomandi,M.,Kelso, R.,2015. A Study of Long Separation Bubble on Thick Airfoils and its Consequent Effects,International Journal of Heat and Fluid Flow52: 84-96.

3.Genç, M.S., Karasu, İ., Açıkel, H.H., Akpolat, M.T.,2012. Low Reynolds Number flows and Transition, Low Reynolds Number Aerodynamics and Transition, Editor: M. Serdar GENÇ. ISBN 979-953-307-627-9, Intech-Sciyo.

4.Singh, R.K., Ahmed, M.R., Zullah, M.A., Lee, Y.H.,2012. Design of a Low Reynolds Number Airfoil for Small Horizontal Axis Wind Turbines,Renewable energy42: 66-76.

5.Genç,M.S., İlyas,K., H. Hakan,A.,2012. An Experimental Study on Aerodynamics of NACA2415 Aerofoil at Low Re Numbers,Experimental Thermal and Fluid Science39: 252-264.

6.Karasu, İ., Genç, M.S., Açikel, H.H., 2013. Numerical Study on Low Reynolds Number Flows Over an Aerofoil,J. Appl. Mech. Eng2.5:131.

7.Shah, H., Kitaba, J., Mathew, S., Lim, C.M., 2014. Experimental FlowVisualization Over a Two-dimensional Airfoil at Low Reynolds Number,Engineering and Technology (BICET 2014), 5thBrunei International Conference on. IET.

8.Roberts, W.B.,1980. Calculation of Laminar Separation Bubbles and Their Effect on Airfoil Performance,AIAA Journal18.1: 25-31.

9.Mueller, Thomas,J., 1985.The Influence of Laminar Separation and Transition on Low Reynolds Number Airfoil Hysteresis,Journal of Aircraft22.9: 763-770.

10.Cesini, G., Ricci, R., Montelpare, S., Silvi, E.,2002. A Thermographic Method to Evaluate Laminar Bubble Phenomena on Airfoil Operating at Low Reynolds Number, Quantitative InfraRed Thermography 6. 101-107.

11.Genç, M.S., Akpolat, M.T., Açıkel, H.H., Karasu, İ.,2012. An Experimental Study of Perpendicular Acoustic Disturbances Effect on Flow Over an Aerofoil at Low Reynolds Numbers,ASME 2012 International Mechanical Engineering Congress and Exposition,American Society of Mechanical Engineers.

12.Gordnier, Raymond E., Peter,E., Attar, J.,2014. Impact of Flexibility on the Aerodynamics of an Aspect Ratio Two Membrane Wing,Journal of Fluids and Structures45: 138-152.

13.Rojratsirikul, P., Genc, M.S., Wang, Z., Gursul, I.,2011. Flow-induced Vibrations of Low Aspect Ratio Rectangular Membrane Wings,Journal of Fluids and Structures27.8: 1296-1309.

14.Genç, M.S., Karasu, İ., Açıkel, H.H., Akpolat, M.T., Özkan, G.,2016. Acoustic Control of Flow Over NACA 2415 Aerofoil at Low Reynolds Numbers."Sustainable Aviation. Springer International Publishing,p.375-420.

15.Açıkel, H.H.,Genç, M.S.,2016. Flow Control With Perpendicular Acoustic Forcing on NACA 2415 Aerofoil at Low Reynolds Numbers,Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering,0954410015625672.

16.Xue, S., Johnson, B., Chao, D., Sareen, A., Westergaard, C.,2010. Advanced Aerodynamic Modeling of Vortex Generators for Wind Turbine Applications,European Wind Energy Conference (EWEC), Warsaw Poland.

17.Øye, S.,1995. The Effect of Vortex Generators on the Performance of the ELKRAFT 1000 kw Turbine,9thIEA Symposium on Aerodynamics of Wind Turbines, Stockholm, ISSN.

18.Lin, John C.,2002. Review of Research on Low-profile Vortex Generators to Control Boundary-layer Separation,Progress in Aerospace Sciences38.4: 389-420.

19.Koca,K., Genç, M.S., Açikel,H.H., 2016. Roughness Effect on Flow over Wind Turbine Airfoil, The International Symposium on Sustainable Aviation (ISSA-2016), 29 May-1 June 2016, Istanbul, Turkey.