شبیه سازی و بهینه سازی پارامترهای هیدرولیکی جریان آشفته در تخلیه کننده های تحتانی سد با استفاده از Open FOAM

محورهای موضوعی : Business Administration and Entrepreneurship

مهدی قبادی ¹ , سینا فرد مرادی نیا ²

1 - دانش آموخته کارشناسی ارشد مهندسی عمران-آب و سازه‌های هیدرولیکی،گروه مهندسی عمران، واحد تبریز، دانشگاه آزاد اسلامی، تبریز، ایران
2 - گروه مهندسی عمران، واحد تبریز، دانشگاه آزاد اسلامی، تبریز، ایران/ مرکز تحقیقات رباتیک و فناوری‌های نرم، واحد تبریز ، دانشگاه آزاد اسلامی، تبریز، ایران

تاریخ دریافت : 1401/11/25 تاریخ پذیرش : 1402/11/25 تاریخ انتشار : 1403/02/01

کلید واژه: دینامیک سیالات محاسباتی, ضریب تخلیه, تخلیه کننده تحتانی سد, Open FOAM, اگوریتم ژنتیک,

چکیده مقاله :

استفاده از روش های عددی به طور گسترده در تشخیص عملکرد سیستم های هیدرولیکی و بهینه سازی آنها مورد استفاده قرار می گیرد. مدل سازی عددی هزینه کمتری نسبت به کار تجربی دارد. روش های عددی می توانند برای بررسی صحت نتایح و مقایسه بین آنها نیز مورد بهره برداری قرار بگیرند. در این پایان نامه روش حجم سیال برای شبیه سازی جریان سطح آزاد آب در داخل تخلیه کننده تحتانی سد کانی رش مورد استفاده قرار گرفته است. از آنحاییکه جریان در داخل تخلیه کننده ها به صورت آشفته است، از مدل های توربولانسی k-ε ، k-ε RNG ، k-ω SST ، k-ω و همچنین LES استفاده و مقایسه شده اند. همچنین ضریب تخلیه در داخل تخلیه کننده تحتانی و دبی هوادهی نیز مورد بررسی و مقایسه قرار گرفته است. نتایج بیانگر این مطلب است که روش عددی استفاده شده در اپن فوم، با کارهای تجربی تطابقت بسیار خوبی دارد، مخصوصاَ در مدل توربولانسی k-ω نسبت به k-ε. نتایج بیانگر این مطلب بود که در درصد خطا شبیه سازی برای ضریب تخلیه چیزی در حدود ۷ درصد می باشد و نتایج بهینه و شبیه سازی برای دبی هوادهی نیز به ترتیب برابر مقدار 20 و 24 متر مکعب بر ساعت است. همچنین مشخص گردید که با افزایش قطر هیدرولیکی، ضریب تخلیه افزایش می یابد و با افزایش طول تخلیه کننده تحتانی، ضریب تخلیه دچار کاهش می شود. انتخاب بهینه طول تخلیه کننده تحتانی وابسته به ارتفاع پشت سد می باشد.

چکیده انگلیسی:

Abstract
Introduction: The use of numerical methods is widely used in diagnosing the performance of hydraulic systems and optimizing them. Numerical modeling is less expensive than experimental work. Numerical methods can be used to check the accuracy of the results and compare them. In this thesis, the fluid volume method is used to simulate the free surface flow of water inside the lower discharger of Kani Sib Dam. Since the flow inside the dischargers is turbulent, k-ε, k-ε RNG, k-ω SST, k-ω and also LES turbulence models have been used and compared. Also, the discharge coefficient inside the lower discharger and the aeration flow have been investigated and compared.
Methods: To simulate the turbulent flow inside the lower discharger, continuity equations, momentum, energy and equation of state along with equations related to the aforementioned turbulence models have been solved using OpenFoam software.  The set of equations of conservation of mass, conservation of momentum and energy for turbulent flow, which are so-called Reynolds averaging equations, are the governing equations of the flow and are used to model the flow by solving them numerically.
Findings: The simulation and optimization of the hydraulic parameters of the turbulent flow in the lower dischargers of the Sib Mineral Dam has been completed using OpenFOAM. The results have been made on the parameters of the lower discharger of Sib mineral dam. And the optimization is done using genetic algorithm. In this research, it was found that with the increase of the hydraulic diameter, the discharge coefficient increases. Also, with the increase of the hydraulic diameter, the core of the water fluid jet inside the discharger undergoes a strong fluctuation, which can increase the shear stress. An excessive increase in shear stress can cause corrosion of the discharge walls. On the other hand, with a further decrease in shear stress, deposition inside the lower discharger increases. At the same time, with the increase in the length of the lower discharger, the discharge coefficient decreases. The optimal selection of the length of the lower drain depends on the height behind the dam. As the opening rate increases, the discharge coefficient also increases and the k- ε turbulence model gives more acceptable results to estimate the results. Finally, for each aeration flow rate, a set of optimal values for the discharge coefficient and the opening rate has been obtained.

منابع و مأخذ:

1.       Ghazali, F., Salehi Neishabori, A.A., and Kavianpour. 2014. Numerical analysis of the effect of channel geometry on flow aeration in the lower discharger of the dam. Hydroelectric dam and power station journal, 1(1): 33-39.‎

2.       Zounemat-Kermani, M., Rajaee, T., Ramezani-Charmahineh, A., and Adamowski, J.F. 2017. Estimating the aeration coefficient and air demand in bottom outlet conduits of dams using GEP and decision tree methods. Flow Measurement and Instrumentation, 54: 9-19.

3.       Xie, Q., Liu, J., Han, B., Li, H., Li, Y., and Li, X. (2019). Experimental and Numerical Investigation of Bottom Outlet Leakage in Earth-Fill Dams. Journal of Performance of Constructed Facilities, 33(3), 04019037.

4.       Khurshidi, H., Taleb Bidakhti, N., and Nik Sarasht A. H. 2008. Numerical modeling of flow and aeration system in the lower discharger of Sefidroud Dam. Journal of civil Engineering Islamic Azad university, 1(2): 37-45.

5.       Moghimi, M. 2019. Experimental and numerical investigation of bottom outlet hydraulic model. Journal of Computational & Applied Research in Mechanical Engineering (JCARME), 8(2): 153-164.

6.       Kenn, M. J., Garrod, A. D., BALDASSARRINI, M., BINNIE, G., BURGESS, J., PALMER, M., and ACKERS, P. 1981. DISCUSSION. CAVITATION DAMAGE AND THE TARBELA TUNNEL COLLAPSE OF 1974. Proceedings of the Institution of Civil Engineers, 70(4): 779-810.

7.       Safavi, K., Zarrati, A. R., and Attari, J. 2008, April. Experimental study of air demand in high head gated tunnels. In Proceedings of the Institution of Civil Engineers-Water Management Vol. 161, No.2: 105-111. Thomas Telford Ltd.

8.       Dargahi, B. 2010. Flow characteristics of bottom outlets with moving gates. Journal of Hydraulic Research, 48(4): 476-482.

9.       Kolachian, R., Abbaspour, A., aand Salmasi, F. 2012. Aeration in bottom outlet conduits of dams for prevention of cavitatio Aeration in bottom outlet conduits of dams for prevention of cavitation.nd Urbanism, 2(5): 196-201.

10.   Yazdi, J., and Zarrati, A.R. 2011. An algorithm for calculating air demand in gated tunnels using a 3D numerical model. Journal of Hydro-environment Research, 5(1): 3-13.

11.   Daneshmand, F., Adamowski, J., and Liaghat, T. 2014, March. Bottom outlet dam flow: physical and numerical modelling. In Proceedings of the Institution of Civil Engineers-Water Management, Vol. 167, No.3: 176-184. Thomas Telford Ltd.

12.   Shamsai , A., Soleymanzadeh, R. 2006. Numerical simulation of Air-Water flow in bottom outlet, International Journal of Civil Engineering, 4(1): 14-33.

13.   Ghazali, F., Salehi Nishabouri, A.A., and Kavianpour, 2010. Numerical analysis of the effect of channel geometry on flow aeration, M.R.-80 in the dam's lower drain. The first international conference and the third conference National dam and power plants Blue p. 20th and 19th of Bahman, Tehran, Iran, Tehran, 62.

14.   Najafi, M.R., and Zarrati, A.R. 2010. Numerical simulation of air–water flow in gated tunnels, Water Management, 163: 289-295.

15.   Mardani, M., Rahimzadeh, H. and Sarkardeh H. 2015. analysis and investigation of the use of blocks in the operation of Houzcheh. 8 Madras Mechanical Engineering Scientific-Research Journal: 15(6): 31-41.

16.   Khanarmoui, M. Rahimzadeh, H. and Sarkardeh, H. 2015. Investigating the effect of intake withdrawal direction on critical submergence and strength of vortices. Modares Mechanical Engineering, 14(10): 35-42.

17.   Roshan, R., Azamathulla, H.M.D., Marosi, M., Sarkardeh, H., Pahlavan, H. and Ghani, A.B. 2010. Hydraulics of Stepped Spillways with Different Numbers of Steps, Journal of Dams and Reservoirs (ICE), 20, 3: 131-136.

18.   Khodashenas, S.R., Sarkardeh, H., Marosi, M., and Safavi, K.H. 2010. Vortex Study at Orifice Spillways of Karun III Dam, Journal of Dam Engineering, 2:131-142.

19.   Rahimzadeh, H., Abdolahpour, M., Roshan, R. and Sarkardeh, H. 2012. Hydraulic Optimization of Flow Over a Gated Spillway, Journal of Dam Engineering, 22(4): 1.

20.   Taghvaei, S.M., Roshan, R., Safavi, K.H., and Sarkardeh, H. 2012. Anti-Vortex Structures at Hydropower Dams, International Journal of the Physical Sciences, 7(28): 5069-5077.

21.   Jorabloo, M., Maghsoodi, R. and Sarkardeh, H. 2011. 3D Simulation of Flow over Flip Buckets at Dams, Journal of American Science, 7(6): 931-936.

22.   Maghsoodi, R., Roozgar, M.S., Chau, K.W. and Sarkardeh, H. 2012. 3D Simulation of Dam Break Flows, Journal of Dam Engineering, 2: 1-17.

23.   Launder, B.E., and Spalding, D.B. 1983. The numerical computation of turbulent flows. In Numerical prediction of flow, heat transfer, turbulence and combustion, pp. 96-116.

24.   Menter, F. 1993. Zonal two equation kw turbulence models for aerodynamic flows. In 23rd fluid dynamics, plasmadynamics, and lasers conference, pp. 2906.

25.   Moukalled, F., Mangani, L., and Darwish, M. 2016. The finite volume method in computational fluid dynamics. An advanced introduction with OpenFoam® and Matlab®. Nueva York: Springer.

26.   Doan, M.N., Alayeto, I.H., Kumazawa, K., and Obi, S. 2019, July. Computational fluid dynamic analysis of a marine hydrokinetic crossflow turbine in low Reynolds number flow. In Fluids Engineering Division Summer Meeting, Vol. 59032: V002T02A067. American Society of Mechanical Engineers.

27.   Tullis, B.P., and Larchar, J. 2011. Determining air demand for small- to medium-sized embankment dam low-level outlet works. Journal of Irrigation and Drain Engineering, 137: 793-800.

28.   Sharma, H.R. 1976. Air-entrainment in high head gated conduits. Journal of Hydraulic Division, 102, 11:1629–1646.