افزایش راندمان رسوب شویی تحت فشار مخزن سد با استفاده از سازه اتاقک رسوب

نوع مقاله: مقاله پژوهشی

نویسندگان

1 عضو هیات علمی دانشگاه زنجان

2 گروه مهندسی آب، پردیس ابوریحان، دانشگاه تهران

چکیده

در چند دهه اخیر به دلیل افزایش جمعیت و نیاز فزاینده به آب، سد سازی توسعه پیدا کرده است، اما پدیده رسوب گذاری داخل مخازن سد‌ها همواره باعث کاهش کارایی و طول عمر مخازن بوده است. در این تحقیق با نصب سازه منشوری شکل تحت عنوان اتاقک رسوب در جلوی تخلیه کننده تحتانی، تاثیر این سازه بر راندمان رسوب شویی تحت فشار مورد بررسی قرار گرفت. در این سازه، در دیواره جلویی و کناری آن، شکاف های عمودی با عرض باز شدگی (b)، تعداد و آرایش مختلف (موقیعت) تعبیه گردید. شکاف‌ها در سه حالت تکی، دوتایی و سه تایی با بازشدگی‌های 1/25-7/5 سانتی‌متر (0/25، 0/5، 1 و 1/5= b/D و D قطر دریچه تخلیه) انتخاب گردید. نتایج آزمایش ها نشان داد که در مدل‌های دو شکاف جلویی با مجموع بازشدگی 5 سانتی‌متر (1 =b/D)، با افزایش فاصله شکاف‌ها راندمان رسوب شویی افزایش 100 درصدی نشان داد. همچنین در مدل‌های دو شکاف کناری متقارن با مجموع بازشدگی 5 سانتی‌متر (1= b/D)، با فاصله گرفتن شکاف‌ها از دیواره کناری مخزن، راندمان رسوب شویی به میزان 50 درصد افزایش یافت. در مدل‌های سه شکاف متقارن با مجموع بازشدگی 5 سانتی‌متر (1 =b/D)، افزایش تعداد شکاف‌ها نتوانست راندمان رسوب شویی را افزایش دهد. در مدل‌های دو شکاف ترکیبی (ترکیب یک شکاف در دیوار جلویی با یک شکاف در دیوار کناری) با مجموع بازشدگی 5 سانتی‌متر (1 =b/D)، راندمان رسوب شویی افزایش چشمگیری نشان داد، به‌طوری که راندمان رسوب‌شویی در این مدل افزایش 50 درصدی نسبت به مدل دو شکاف کناری متقارن نشان داد.

کلیدواژه‌ها


عنوان مقاله [English]

Enhancement the Pressurized Flushing Efficiency of Dam Reservoir Using Sediment Chamber Structure

نویسندگان [English]

  • Ghorban Mahtabi 1
  • Saeed Mozafari 2
1 Water engineering, University of Zanjan
2 University of Tehran
چکیده [English]

َAbstract:
In the recent decades, Dams construction have been developed due to the increasing of population and the growing need for water. However, phenomenon of sediment deposition inside the reservoirs has always caused to reduce the efficiency and life time of reservoirs. In this study, by installing a prismatic structure named the sediment chamber in front of bottom outlet, effect of this structure on increasing the pressurized flushing efficiency was investigated. In this structure, in its front and side walls, vertical slots with different opening width (b), number and arrangement were considered. Slits were selected in three modes of single, binary and triple with 1.25-7.5 centimeter openings. Experimental results showed that in models with two front slot and a total opening of 5 cm (b/D=1), the flushing efficiency showed a 100% increase with increasing of slot distance. Also in models with two symmetrical side slots and a total opening of 5 cm (b/D=1), with going away the slots from the side wall of sediment tank, the flushing efficiency increased by 50%. In the models with three symmetric slots and a total opening of 5 cm (b/D=1), increasing the number of slots could not increase the flushing efficiency. In the models with two combined slots (combining a slot in the front wall with a slot in the side wall) with a total openings of 5 cm(b/D=1), flushing efficiency showed a significant increase, so that flushing efficiency of this model showed a 50% increase with respect to the models with two symmetrical side slots.

Abstract:
In the recent decades, Dams construction have been developed due to the increasing of population and the growing need for water. However, phenomenon of sediment deposition inside the reservoirs has always caused to reduce the efficiency and life time of reservoirs. In this study, by installing a prismatic structure named the sediment chamber in front of bottom outlet, effect of this structure on increasing the pressurized flushing efficiency was investigated. In this structure, in its front and side walls, vertical slots with different opening width (b), number and arrangement were considered. Slits were selected in three modes of single, binary and triple with 1.25-7.5 centimeter openings. Experimental results showed that in models with two front slot and a total opening of 5 cm (b/D=1), the flushing efficiency showed a 100% increase with increasing of slot distance. Also in models with two symmetrical side slots and a total opening of 5 cm (b/D=1), with going away the slots from the side wall of sediment tank, the flushing efficiency increased by 50%. In the models with three symmetric slots and a total opening of 5 cm (b/D=1), increasing the number of slots could not increase the flushing efficiency. In the models with two combined slots (combining a slot in the front wall with a slot in the side wall) with a total openings of 5 cm(b/D=1), flushing efficiency showed a significant increase, so that flushing efficiency of this model showed a 50% increase with respect to the models with two symmetrical side slots.

َAbstract:
In the recent decades, Dams construction have been developed due to the increasing of population and the growing need for water. However, phenomenon of sediment deposition inside the reservoirs has always caused to reduce the efficiency and life time of reservoirs. In this study, by installing a prismatic structure named the sediment chamber in front of bottom outlet, effect of this structure on increasing the pressurized flushing efficiency was investigated. In this structure, in its front and side walls, vertical slots with different opening width (b), number and arrangement were considered. Slits were selected in three modes of single, binary and triple with 1.25-7.5 centimeter openings. Experimental results showed that in models with two front slot and a total opening of 5 cm (b/D=1), the flushing efficiency showed a 100% increase with increasing of slot distance. Also in models with two symmetrical side slots and a total opening of 5 cm (b/D=1), with going away the slots from the side wall of sediment tank, the flushing efficiency increased by 50%. In the models with three symmetric slots and a total opening of 5 cm (b/D=1), increasing the number of slots could not increase the flushing efficiency. In the models with two combined slots (combining a slot in the front wall with a slot in the side wall) with a total openings of 5 cm(b/D=1), flushing efficiency showed a significant increase, so that flushing efficiency of this model showed a 50% increase with respect to the models with two symmetrical side slots.

کلیدواژه‌ها [English]

  • Bottom Outlet
  • flushing
  • Slot arrangement
  • Vortex Flow

مقالات آماده انتشار، پذیرفته شده
انتشار آنلاین از تاریخ 30 دی 1398
  • تاریخ دریافت: 27 مهر 1398
  • تاریخ بازنگری: 28 دی 1398
  • تاریخ پذیرش: 30 دی 1398