تأثیر آرایش شعاعی صفحات مستغرق در افزایش راندمان رسوب‌شویی مخزن سد

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی سابق کارشناسی ارشد سازه‌های آبی، گروه مهندسی آب، دانشکده کشاورزی، دانشگاه زنجان

2 استادیار گروه مهندسی آب، دانشکده کشاورزی، دانشگاه زنجان

چکیده

رسوب­شویی تحت فشار یک از روش­های رایج در رسوب­شویی هیدرولیکی مخازن سد است. در این روش، رسوباتی که در مخزن ته­نشین شده­اند، به­وسیله دریچه تخلیه تحتانی سد همراه با جریان آب خروجی تخلیه می­شوند. در این تحقیق با کارگذاری صفحات مستغرق با آرایش شعاعی در جلوی تخلیه کننده، تأثیر این آرایش در افزایش قدرت جریان گردابی و افزایش عملکرد رسوب­شویی تحت فشار مورد آزمایش قرار گرفت. تأثیر پارامترهای مختلف آرایش شعاعی شامل فاصله میانی صفحات اصلی(Lm)، فاصله مابین صفحات اصلی و جانبی (Ls) و فاصله صفحات جانبی از دیواره (Lv) بر روی این پدیده در سه عمق مختلف آب مخزن (20، 30 و 40 سانتی­متر) بررسی گردید. براساس نتایج، مقادیر بهینه طول­های بی­بعد پارامترهای آرایش شعاعی 5/0 Lm/D=، 25/0 Ls/D= و 2/0 Lv/D= به­دست آمد (D، قطر دریچه تخلیه تحتانی). در بهترین آرایش شعاعی صفحات و در شرایط هیدورلیکی مختلف، عملکرد رسوب­شویی به­طور متوسط در حدود 33/11 برابر نسبت به مدل شاهد افزایش یافت. در آرایش شعاعی، با افزایش عمق آب مخزن، عملکرد رسوب­شویی افزایش یافت. این شرایط یعنی رسوب­شویی بیشتر در عمق بالا، یک مزیت نسبی برای اجرای رسوب­شویی است. به­عبارت دیگر، عملیات رسوب­شویی در حالت مخزن پر راندمان بالایی داشته و نیاز به تخلیه آب مخزن نیست.
 

کلیدواژه‌ها


عنوان مقاله [English]

Effect of Radial Arrangement of Submerged Vanes in Increasing the Flushing Efficiency of Dam Reservoir

نویسندگان [English]

  • S Karimi 1
  • G Mahtabi 2
1 M.Sc. Student, Dept., of Water Engineering, Faculty of Agric., Univ. of Zanjan, Zanjan, Iran
2 Assist. Prof., Dept., of Water Engineering, Faculty of Agric., Univ. of Zanjan, Zanjan, Iran
چکیده [English]

Pressurized flushing is one of the common methods in hydraulic flushing of dam reservoirs. In this method, sediments settled in the reservoir are released out together with water flow using the bottom outlet of the dam. In this research, by employing the submerged vanes with radial arrangementin front of the bottom outlet, effect of this arrangement in enhancement of the vortex flow and pressurized flushing efficiency were investigated. The effect of different parameters of radial arrangement including cross distance of the main vanes (Lm), distance between the main and side vanes (Ls) and the distance of vanes from the side wall (Lv) on this phenomenon were investigated in three different water depths of the reservoir (20, 30 and 40 cm). Based on the results, the optimal non-dimensional lengths values of the radial arrangement parameters were obtained as Lm/D=0.5, Ls/D= 0.25 and Lv/D=0.2 (D, diameter of bottom outlet). In the best radial arrangement parameters of the vanes in the different hydraulic condition, flushing efficiency increased about 11.33 times compared to the control model. In radial arrangement, with increasing the water depth of reservoir, the flushing performance increased. This condition, more flushing in high water depth, is a comparative advantage for flushing. In other words, the flushing operation has more efficiency in the full condition of the reservoir and it is not necessary to empty the reservoir.
 

کلیدواژه‌ها [English]

  • Flushing
  • Main submerged vanes
  • Radial arrangement
  • Side submerged vanes
  • Water depth
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