ساختارهای آشفتگی جریان در ناحیه دنباله یک توربین باد به روش شبیه‌سازی گردابه‌های بزرگ

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی مکانیک، دانشگاه سیستان و بلوچستان، زاهدان، ایران

2 دانشکده مهندسی مکانیک، دانشگاه بزرگمهر قائنات، قاین، ایران

چکیده

در کار حاضر جریان حول یک توربین باد محور افقی با استفاده از روش شبیه سازی گردابه‌های بزرگ در سرعت‌های دورانی مختلف مطالعه شده است. نتایج نشان می‌دهند که افزایش سرعت دورانی باعث افت بیشتر سرعت در پایین دست جریان می‌شود. برای مثال در فاصله 1D پس از توربین باد در 6= λ2 سرعت کمینه 52 درصد سرعت اولیه است و پس از طی مسافت 6D این مقدار به 67 درصد سرعت اولیه می‌رسد. در 10 = λ3 سرعت کمینه 26 درصد سرعت اولیه است و پس از طی مسافت 6D این مقدار به 68 درصد سرعت اولیه می‌رسد. بسامد گردابه‌های جدا شده از پره با افزایش سرعت دورانی افزایش می‌یابند. گردابه‌های جدا شده از پره تمایل به پخش شدن در جهت عمودی دارند و با افزایش سرعت دورانی شدت پخش آن در جهت عمودی بیشتر می‌شود. تقویت گردابه‌ها در ناحیه دنباله دور در سرعت‌های دورانی بالاتر تنها بخاطر افزایش شدت چرخش نیست، بلکه بخاطر برخورد گردابه‌ها به یکدیگر و تشکیل گردابه‌های جدیدتر است. این موضوع در کارهای گذشته گزارش نشده است. همچنین افزایش شدت آشفتگی و تنش‌های برشی رینولدز در جهت جریان، بخاطر برش شدید جریان باد و تولید مکانیکی انرژی سینتیکی آشفتگی است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Turbulent Structures in the Wake of a Wind Turbine Using Large Eddy Simulation

نویسندگان [English]

  • A. Veisi 1
  • M.H. Shafiei Mayam 2
1 Department of Mechanical Engineering, Sistan and Baluchestan University, Zahedan, Iran
2 Department of Mechanical Engineering, Bozorgmehr-University of Qaenat, Qaen, Iran
چکیده [English]

In the present work the flow around a horizontal axis wind turbine has been studiedusing large Eddy simulation at different rotational speeds. The results show increasing rotational speedscauses a higher velocity deficit in the downstream direction. For example, in 1D after the wind turbinethe minimum velocity is 54% of the initial velocity and reach to the 67% of the initial velocity after waketravel 6D. At the rotational speed of λ3= 10 the minimum velocity is 26% of the initial velocity and reachto the 68% of the initial velocity after wake travel 6D. The frequency of vortex shedding is increasedby increasing the rotational speeds. Shed vortices tend to be extended in the y direction and its intensityaugmented by increasing the rotational speeds. The strengthen of vortices at higher rotational directionin far wake region not only due to the increased of swirling strength, but it is also due to the collision ofvortices and the formation of new vortices. This issue has not been reported in previous works. Also, theincrease of turbulence intensity and Reynolds shear stress in the flow direction is due to the severe windshear and high mechanical production of turbulent kinetic energy.

کلیدواژه‌ها [English]

  • Wind turbine
  • Large Eddy Simulation
  • Turbulent flow
  • turbulence structures
[1] Chen, D., Zhang, W., Exploitation and research on wind energy, Energy Conservation Technology, 4(1) (2007) 339–343.
[2] Li, Y., Paik, KJ., Xing, T., Carrica, PM., Dynamic overset CFD simulations of wind turbine aerodynamics, Renewable Energy, 37(1) (2012) 285–298.
[3] Grant, I., Parkin, P., Wang, X., Optical vortex tracking studies of a horizontal axis wind turbine in yaw using laser-sheet, flow visualization, Experiments in Fluids, 23(6) (1997) 513–519.
[4] Zhang, W., Markfort, CD., Porté-Agel, F., Nearwake flow structure downwind of a wind turbine in a turbulent boundary layer, Experiments in Fluids, 52(5) (2012) 1219–1235.
[5] Vermeer, LJ., Sorensen, JN., Crespo, A., Wind turbine wake aerodynamics, Progress in Aerospace Sciences, 39(6) (2003) 467–510.
[6] Mo, JO., Choudhry, A., Arjomandi, M., Kelso, R., Lee, YH., Effects of wind speed changes on wake instability of a wind turbine in a virtual wind tunnel using large eddy simulation, J Wind Eng Ind Aerodyn, 117(1) (2013) 38–56.
[7] Mo, JO., Choudhry, A., Arjomandi, M., Lee, YH., Large eddy simulation of the wind turbine wake characteristics in the numerical wind tunnel model, J Wind Eng Ind Aerodyn. 112(1) (2013) 11–24.
[8] Aubrun, S., Loyer, S., Hancock, PE., Hayden, P., Wind turbine wake properties: Comparison between a nonrotating simplified wind turbine model and a rotating model, Journal of Wind Engineering and Industrial Aerodynamics, 120(1) (2013) 1–8.
[9] Sarlak, H., Meneveau, C., Sørensen, JN., Role of subgridscale modeling in large eddy simulation of wind turbine wake interactions, Renew Energy, 77(1) (2015) 386–399.
[10] Hu, H., Yang, Z., Sarkar, P., Dynamic wind loads and wake characteristics of a wind turbine model in an atmospheric boundary layer wind, Experiments in Fluids, 52(5), (2012) 1277–1294.
[11] Maeda, T., Kamada, Y., Murata, J., Yonekura, S., Ito, T., Oawa, A., Kogaki, T., Wind tunnel study on wind and turbulence intensity profiles in wind turbine wake, Journal of Thermal Science, 20(2) (2011) 127–132.
[12] Zhong, H., Du, P., Tang, F., Wang, L., Lagrangian dynamic large-eddy simulation of wind turbine near wakes combined with an actuator line method, Appl Energy, 144(1) (2015) 224–233.
[13] Porté-Agel, F., Wu, YT., Lu, H., Conzemius, RJ., Largeeddy simulation of atmospheric boundary layer flow through wind turbines and wind farms, J Wind Eng Ind Aerodyn, 99(1) (2011) 154–168.
[14] Jimenez, A., Crespo, A., Migoya, E., Garcia, J., Advances in large-eddy simulation of a wind turbine wake, J Phys Conf Ser., (2007).
[15] Giahi, MH., Jafarian Dehkordi, A., Investigating the influence of dimensional scaling on aerodynamic characteristics of wind turbine using CFD simulation, Renew Energy, 97(1) (2016) 162–168.
[16] Meyers, J., Meneveau, C., Optimal turbine spacing in fully developed wind-farm boundary layers, Wind energy, 15(1) (2012) 305-317.
[17] Chu, CR., Chiang, PH., Turbulence effects on the wake flow and power production of a horizontal-axis wind turbine, J Wind Eng Ind Aerodyn, 124(1) (2013) 82– 89.
[18] Park, J., Law, KH., Layout optimization for maximizing wind farm power production using sequential convex programming, Appl Energy, 151(1) (2015) 320–334.
[19] Krogstad, PÅ., Eriksen, PE., Blind test calculations of the performance and wake development for a model wind turbine, Renewable Energy, 50(1) (2013) 325–333.
[20] Pope, SB., Turbulent Flows, Cambridge University Press, (2000) 351-558.
[21] Smagorinsky, J., General Circulation Experiments With the Primitive Equations, Mon. Weather Rev, 91(3) (1963) 99–164.
[22] Tangler, JL., Somers, DM., NREL airfoil families for HAWTs, Proceedings of the American Wind Energy Association Wind power Conference, (1995).
[23] Somers, D., Design and experimental results for the S825 Airfoil, , National Renewable Energy Laboratory, Technical Report NREL/SR-500-36344, (1999).
[24] Alfredsson, PH., Dahlberg, JA., Vermeulen, PEJ., A comparison between predicted and measured data from wind turbine wakes, Wind Engineering, 6(3) (1982) 149–155.
[25] Medici, D., Alfredsson, PH., Measurements on a wind turbine wake: 3D Effects and bluff body vortex shedding, Wing Energy, 9(3) (2006) 219–236.
[26] Kim, J., Evolution of a vortical structure associated with the bursting event in a channel flow, Turbulent Shear Flow 5, Springer-Verlag, Berlin, (1985) 221–233.
[27] Jeong, J., Hussai, F., On the identification of a vortex, J. of Fluid Mechanics, 285(1) (2006) 69-94.
[28] Perry, A.E., Chong, M.E., Cantwell, B.J., A general classification of three-dimensional flow fields, J. Physics of Fluids, 2(1) (1990) 765-777.
[29] Hunt, JCR., Wray, AA., Moin, P., Eddies, streams, and convergence zones in turbulent flows, Cent. Turbul. Res. Proc., (1988).
[30] Zhou, J., Adrian, RJ., Balachandar, S., Kendall, TM., Mechanism for generating coherent packets of hairpin vortices in channel flow, Journal of Fluid Mechanics, 387(1) (1999) 353-396.
[31] Maciel,Y., Shafiei Mayam, MH,. Hairpin structures in a turbulent boundary layer under stalled-airfoil-type flow conditions , Progress in Turbulence III,Proceedings of the iTi Conference in Turbulence, Bertinoro, Italy, (2008).
[32] Shafiei Mayam, M.H., Maciel, Y., Hairpin structures in a turbulent boundary layer with strong adverse pressure gradient, International Symposium on turbulence and shear flow phenomena (TSFP), Munich, Germany, (2007).
[33] Shafiei Mayam M.H., Maciel Y., Coherent structures in a turbulent boundary layer in stalled-air foil type flow conditions, AERO Conference and 54th Annual General Meeting, Toronto, Canada, (2007).
[34] Shafiei Mayam, MH., Yvan Maciel, Statistical properties of hairpin vortices in a turbulent boundary layer under stalled-airfoil-type flow conditions, The 18th Annual ISME Conference, Sharif University of Technology, Iran, (2010).
[35] VEISI, AA., Shafiei Mayam, MH., Large Eddy Simulation of flow around a single and two in-line horizontal-axis wind turbines, Energy, 121(1) (2017) 533-544.
[36] Veisi, AA., Shafiei Mayam, MH., Effects of blade rotation direction in the wake region of two in-line turbines using Large Eddy Simulation, Appl Energy, 197(1) (2017) 375-392.
[37] Sherry, M., Sheridan, J., Lo, Jacono, D., Characterization of a Horizontal Axis Wind Turbine’s Tip and Root Vortices, Exp. in Fluids, 54(3) (2013) 1417.
[38] Hu, H., Tian, W., Ozbay, A., Experimental Investigation on the Wake Characteristics and Aeromechanics of Dual- Rotor Wind Turbines, J Eng Gas Turbines Power, 138(1) (2016) 1–17.
[39] Eriksen, PE., Krogstad, PE., Development of coherent motion in the wake of a model wind turbine, Renewable Energy, doi: 10.1016/j. renene.2017.02.031, (2017).
[40] Sarmast, S., Numerical study on instability and interaction of wind turbine wakes, in Mechanics, Stability, Transition and Control, PhD Thesis, KTH: Stockholm, Sweden, (2013).