شبیه‌سازی عددی توزیع رسوب در حوضچه رسوب‌گیر گردابی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه مهندسی آبیاری و آبادانی، پردیس کشاورزی و منابع طبیعی، دانشگاه تهران، کرج، ایران

2 گروه علوم و مهندسی آب، دانشکده کشاورزی، دانشگاه فردوسی مشهد، مشهد، ایران

چکیده

یکی از چالش­های اساسی در توسعه سیستم­های آبیاری و دیگر شبکه­های انتقال آب، حذف رسوبات موجود در جریان ورودی به این سیستم­ها می­باشد. حوضچه رسوب­گیر گردابی (VSB) یکی از انواع رسوب­گیرهای با اندازه کوچک و راندمان بالاست که با استفاده از گردابه­های جریان، رسوبات را حذف می­کند. مطالعات در مورد طراحی بهینه حوضچه­های رسوب­گیر گردابی عموما بر پایه مدل­های آزمایشگاهی و فیزیکی صورت گرفته است که نیازمند صرف هزینه زیاد بوده و زمان­بر می­باشد. در این پژوهش مدل SSIIM به منظور شبیه­سازی میدان جریان و توزیع رسوب در VSB مورد ارزیابی قرار گرفته و نتایج حاصل از آن با اندازه­گیری­های آزمایشگاهی مقایسه گردید. پس از اطمینان از انطباق نسبی نتایج مدل­سازی با اندازه­گیری­های آزمایشگاهی، اثر پارامترهای طراحی مختلف همچون اندازه ذرات رسوب ورودی، نسبت تخلیه از کف و اختلاف کف کانال­های ورودی و خروجی مورد بررسی قرار گرفت. نتایج نشان داد که از بین پارامترهای طراحی مورد مطالعه، راندمان VSB بیشترین حساسیت را به اندازه رسوبات ورودی نشان می­دهد. با افزایش نسبت تخلیه از کف، راندمان افزایش می­یابد اما این افزایش راندمان در نسبت­های تخلیه بیشتر از 10 درصد کمتر از 4 درصد می­باشد. همچنین افزایش اختلاف کف کانال ورودی و خروجی می­تواند راندمان را تا حدود 18 درصد برای رسوبات ریزدانه افزایش دهد، در حالی که این افزایش راندمان برای رسوبات با اندازه بزرگتر، کمتر از ده درصد می­باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Numerical Simulation of Sediment Distribution in Vortex Settling Basin

نویسندگان [English]

  • Sarem Norouzi 1
  • Alinaghi Ziaei 2
1 Department of Irrigation and Reclamation Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
2 Department of Water Science and Engineering, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
چکیده [English]

One of the main challenges associated with the development of irrigation systems and other water distribution systems is the sediment removal from the inlet channel. Vortex settling basin (VSB) is one of the types of sediment extractors with small size and high efficiency which removes the sediments using the vortices of the flow. Studies on the proper design of VSBs are generally based on experimental and physical models which are highly costly and time-consuming. In this study, SSIIM model was evaluated for the simulation of flow field and sediment distribution in a VSB and the results were compared with experimental measurements. After ensuring the relative agreement of the model results with experimental measurements, the effect of different design parameters such as inlet sediment size, bottom outlet discharge ratio, and bed level difference between inlet and outlet channels were investigated. The results showed that among the design parameters, trap efficiency of the VSB is more sensitive to the sediment size. By increasing the bottom discharge ratio, the efficiency increases, but this increase in the efficiency barely exceed 4 % for bottom discharge ratios higher than 10 %. In addition, increasing the bed elevation difference between the inlet and outlet channels can increase the efficiency up to 18 % for fine-grained sediments, while this increase is less than 10 % for coarse-grained sediments.

کلیدواژه‌ها [English]

  • Vortex settling basin (VSB)
  • Trap efficiency
  • SSIIM numerical model
  • design parameters
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