بررسی آزمایشگاهی استهلاک انرژی در شیب‌شکن‌های قائم مجهز به صفحات مشبک افقی با جریان فوق بحرانی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشیار، گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه مراغه، مراغه، ایران.

2 استادیار گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه مراغه، مراغه، ایران

3 دانشجوی کارشناسی ارشد، گروه مهندسی عمران، دانشگاه مراغه، مراغه، ایران

چکیده

در این مطالعه با هدف افزایش استهلاک انرژی در شیب­شکن­های قائم با جریان فوق بحرانی در بالادست، از صفحات مشبک به صورت افقی در لبه شیب­شکن­ قائم به عنوان مستهلک­کننده انرژی اضافی جریان استفاده گردید. آزمایش­ها برای یک شیب­شکن قائم ساده و شیب­شکن مجهز به صفحات مشبک با دو نسبت تخلخل و سه بازشدگی دریچه تنظیم گردید. در طی آزمایش­ها مشاهده شد که صفحه مشبک افقی بعد از شیب­شکن، با تقسیم جت در حال سقوط به تعداد بسیار زیادی از جت­های کوچک عمودی باعث افزایش تداخل هوا و تلاطم در داخل استخر گردید. مقایسه نتایج نشان داد که استفاده از این صفحات در شیب­شکن­های قائم باعث افزایش عمق نسبی پایین­دست، عمق نسبی استخر و استهلاک انرژی نسبی نسبت به شیب­شکن قائم ساده می­گردد. همچنین با بررسی نتایج مشخص گردید که با افزایش عدد فرود بالادست و کاهش عمق بحرانی نسبی، استهلاک انرژی نسبی افزایش می­یابد. این درحالی است که تخلخل صفحات مشبک تأثیری بر روی این پارامتر ندارد. بررسی و مقایسه نتایج مربوط به شیب­شکن­های قائم ساده و مجهز به صفحه مشبک نشان داد که استفاده از صفحات مشبک افقی در این سازه­ها باعث کاهش طول حوضچه آرامش و حذف سازه حوضچه آرامش می­گردد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Experimental Investigation of Energy Dissipation in Vertical Drops Equipped with a Horizontal Screen under Supercritical Flow

نویسندگان [English]

  • Rasoul Daneshfaraz 1
  • Sına Sadeghfam 2
  • vadoud Hasanniya 3
1 Associate Professor, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran.
2 Assistant Professor, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran.
3 M.Sc. Student, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran.
چکیده [English]

In this study, horizontal screens were used in the edge of vertical drops, as an excessive energy dissipater of flow, to increase dissipation of energy in vertical drops with the supercritical flow at upstream. Experiments adjusted for a simple vertical drop and a drop equipped by screens with two porosity values and three openings of the upstream sluice gate. During the experiments, it was observed that the horizontal screen after drop increased the air entrance and turbulence in the pool due to dividing the falling jet into a large number of small vertical jets. The results indicate that using these plates in the vertical drops increases the relative depth of downstream, relative depth of pool and relative energy dissipation as compared to a simple vertical drop. Also, results showed by increasing the upstream Froude number and decreasing the relative critical depth, the relative energy dissipation increases. However, the porosity of screens has not a significant effect on energy dissipation. Investigation and comparison of the results corresponded to the simple vertical drops and the ones equipped with screens indicated that incorporating the horizontal screens in these structures eliminate or decrease the length of stilling ponds.

کلیدواژه‌ها [English]

  • vertical drop
  • dissipator
  • Froude number
  • downstream depth
Aslankara, V. (2007). Experimental investigation of tailwater effect on the energy dissipation through screens (Doctoral dissertation, MS thesis, Middle East Technical Univ. Ankara, Turkey).
Balkiş, G. (2004). Experimental Investigation of Energy Dissipation through Inclined Screens (Doctoral dissertation, Middle East Technical Univercity, Ankara, Turkey).
Bozkuş, Z., Balkiş, G., & Ger, M. (2005). Effect of inclination of screens on energy dissipation downstream of small hydraulic structures. In Proceedings of the 17th Canadian Hydrotechnical Conference, Edmonton, Alberta, Canada (pp. 881-890).
Bradley, J. N., & Peterka, A. J. (1957). The hydraulic design of stilling basins: hydraulic jumps on a horizontal apron (basin i). Journal of the Hydraulics Division83(5), 1-24.
Çakir, P. (2003). Experimental investigation of energy dissipation through screens (Doctoral dissertation, M. Sc. thesis, Department of Civil Engineering, Middle East Technical University, Ankara, Turkey).
Chamani, M., & Beirami, M. K. (2002). Flow characteristics at drops. Journal of hydraulic engineering, 128(8),788-791.
Chamani, M. R., Rajaratnam, N., & Beirami, M. K. (2008). Turbulent jet energy dissipation at vertical drops. Journal of hydraulic engineering, 134(10), 1532-1535.
Daneshfaraz, R., Sadeghfam, S., & Hasannia, V. (2019a). Experimental investigating effect of Froude number on hydraulic parameters of vertical drop with supercritical flow upstream. AUT Journal of Civil Engineering. Doi: 10.22060/CEEJ.2019.15655.5985 (in Faersi)
Daneshfaraz, R., Chabokpour, J., & Nezafat, H. (2019b). Experimental Investigation of the Scouring due to Hydraulic Jump in Screens. Iranian Journal of Soil and Water Research. 50(5), 1039-1051. (in Faersi)
Daneshfaraz, R., MajediAsl, M., Mirzaee& Nezafat, H. (2019c). The S-jump's Characteristics in the Rough Sudden Expanding Stilling Basin. Iranian AUT Journal of Civil Engineering. Doi: 10.22060/AJCE.2019.16427.5586 (in Faersi)
Daneshfaraz, R., Sadeghfam, S., & Mirzaeereza, R. (2019d). Experimental Study of Expanding Effect and Sand-Roughened Bed on Hydraulic Jump Characteristics. Iranian Journal of Soil and Water Research. 50(4), 885-896. (in Faersi)
Daneshfaraz, R., Sadeghfam, S., & Tahni, A. (2019e). Experimental Investigation of Screen as Energy Dissipators in the Movable-Bed Channel. Iranian Journal of Science and Technology, Transactions of Civil Engineering. Doi: 10.1007/s40996-019-00306-7.
Daneshfaraz, R., Sadeghfam, S., & Ghahramanzadeh, A. (2017). Three-dimensional numerical investigation of flow through screens as energy dissipators. Canadian Journal of Civil Engineering, 44(10), 850-859.
Daneshfaraz, R., Sadeghfam, S., & Rezazadeh-Joudi, A. (2016). Laboratory Investigation on the Effect of Screen’s Location on the Flow Energy Dissipation. Irrigation and drainage structures engineering research, 17(68), 47-62. (in Faersi)
Esen, I. I., Alhumoud, J. M., & Hannan, K. A. (2004). Energy Loss at a Drop Structure with a Step at the Base. Water international, 29(4), 523-529.
Gill, M.A. (1979). Hydraulics of rectangular vertical drop structures. Journal of Hydraulic Research, 17(4), 289-302.
Hager, W. H., & Bremen, R. (1989). Classical hydraulic jump: sequent depths. Journal of Hydraulic Research, 27(5), 565-585.
Hasannia, V., Daneshfaraz, R., & Sadeghfam, S. (2019). Experimental investigating on hydraulic parameters of vertical drop equipped with combined screens. AUT Journal of Civil Engineering. Doi: 10.22060/CEEJ.2019.16431. 6223 (in Faersi)
Hong, Y. M., Huang, H. S., & Wan, S. (2010). Drop characteristics of free-falling nappe for aerated straight-drop spillway. Journal of Hydraulic Research, 48(1), 125-129.
Kabiri-Samani, A. R., Bakhshian, E., & Chamani, M. R. (2017). Flow characteristics of grid drop-type dissipators. Flow Measurement and Instrumentation, 54, 298-306.
Liu, S. I., Chen, J. Y., Hong, Y. M., Huang, H. S., & Raikar, R. V. (2014). Impact Characteristics of Free Over-Fall in Pool Zone with Upstream Bed Slope. Journal of Marine Science and Technology, 22(4), 476-486.
Moore, W. L. (1943). Energy loss at the base of a free overfall. Transactions of the American Society of Civil Engineers, 108(1), 1343-1360.
Nayebzadeh, B., Lotfollahi-yaghin, M. A. & Daneshfaraz, R. (2019). Experimental study of Energy Dissipation at a Vertical Drop Equipped with Vertical Screen with Gradually Expanding at the Downstream. AUT Journal of Civil Engineering. Doi: 10.22060/CEEJ.2019.16493. 6265(in Faersi)
Norouzi Sarkarabad, R., Daneshfaraz, R., & Bazyar, A. (2019). The Study of Energy Depreciation due to the use of Vertical Screen in the Downstream of Inclined Drops by Adaptive Neuro-Fuzzy Inference System (ANFIS). AUT Journal of Civil Engineering. Doi: 10.22060/CEEJ.2019.16694. 6305(in Faersi)
Rajaratnam, N. (1976). Turbulent jets (Vol. 5). Elsevier.
Rajaratnam, N., & Chamani, M. R. (1995). Energy loss at drops. Journal of Hydraulic Research, 33(3), 373-384.
Rajaratnam, N., & Hurtig, K. I. (2000). Screen-type energy dissipator for hydraulic structures. Journal of Hydraulic Engineering, 126(4), 310-312.
Rand, W. (1955). Flow geometry at straight drop spillways. In Proceedings of the American Society of Civil Engineers,81(9), 1-13.
Sadeghfam, S., Akhtari, A. A., Daneshfaraz, R., & Tayfur, G. (2015). Experimental investigation of screens as energy dissipaters in submerged hydraulic jump. Turkish Journal of Engineering and Environmental Sciences, 38(2), 126-138.
Sadeghfam, S., Daneshfaraz, R., & Minaei, o. (2019). Experimental studies on scour of supercritical flow jets in upstream of screens and modelling scouring dimensions using artificial intelligence to combine multiple models (AIMM). Journal of Hydroinformatics, 21 (5): 893-907.
Sharif, M., & Kabiri-Samani, A. (2018). Flow regimes at grid drop-type dissipators caused by changes in tail-water depth. Journal of Hydraulic Research, 1-12.
Tokyay, N. D., & Yildiz, D. (2007). Characteristics of free overfall for supercritical flows. Canadian Journal of Civil Engineering, 34(2), 162-169.
White, M.P. (1943). Discussion of Moore (1943), ASCE, 108, 1361-1364.