بررسی عددی تاثیر ارتفاع و محل تیغه بر رسوب گذاری در حوضچه ته نشینی

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشگاه تربیت مدرس تهران

2 دانشگاه حکیم سبزواری، گروه مهندسی عمران

3 گروه سازه‌های هیدرولیکی، دانشگاه تربیت مدرس، تهران

چکیده

ته نشینی به وسیله نیروی ثقل از معمول­ترین و پرکاربردترین روشهای جداسازی ذرات جامد معلق در آب و فاضلاب می­باشد. حوضچه­های ته­نشینی از اجزاء مهم و اصلی در هر فرآیند تصفیه آب به شمار می­روند. به دلیل هزینه بسیار زیاد ساخت و نگهداری این حوضچه­ها، عملکرد بهینه حوضچه‌های ته­نشینی بسیار حائز اهمیت است. محققان به منظور افزایش کارایی حوضچه، روش‌های مختلفی پیشنهاد کرده­اند که در این میان تغییر هندسه با نصب تیغه در حوضچه­ها جزء روش‌های اقتصادی بوده و نظر محققان را جلب کرده است. ﺩﺭ ﺗﺤﻘﻴﻖ ﺣﺎﺿﺮ ﺟﺮﻳﺎﻥ ﺣﺎﻭﻱ ﺫﺭﺍﺕ رسوب ﺩﺭ ﺣﻮﺿﭽﻪ ته­نشینی ﻣﺴﺘﻄﻴﻠﻲ ﺑﻪ ﺭﻭﺵ ﺣﺠﻢ ﻣﺤﺪﻭﺩ، با استفاده از نرم­افزار Flow3D ﻭ ﺑﺎ ﺍﺳﺘﻔﺎﺩﻩ ﺍﺯ ﻣﺪﻝ ﺁﺷﻔﺘﮕﻲ RNG k-ε ﺑﻪ ﺻﻮﺭﺕ ﺗﻚ­ﻓﺎﺯی ﺷﺒﻴﻪ­ﺳﺎﺯﻱ ﺷﺪﻩ است. هدف از انجام این مطالعه، شبیه­سازی عددی هیدرولیک جریان در حوضچه­های ته­نشینی با آرایش تیغه­های متفاوت و در نهایت دستیابی به بهترین هندسه برای کاربرد تیغه است. با توجه به تطابق نسبتاً ﺧﻮﺏ ﻧﺘﺎﻳﺞ مدل ﻋﺪﺩﻱ ﺣﺎﺿﺮ ﺑﺎ ﺩﺍﺩﻩ­ﻫﺎﻱ ﺁﺯﻣﺎﻳﺸﮕﺎﻫﻲ، ﺍﺯ ﺻﺤﺖ ﻧﺘﺎﻳﺞ ﺷﺒﻴﻪ­ﺳﺎﺯﻱ عددی با نرم­افزار Flow3D ﺍﻃﻤﻴﻨﺎﻥ ﺣﺎﺻﻞ ﺷﺪﻩ است. بررسی نتایج حاصل از این تحقیق نشان می‌دهد جریان در حوضچه­های رسوب­گذار به شدت تحت تاثیر حضور تیغه است. با توجه به مدل­های بررسی شده مشخص گردید حضور تیغه با ارتفاع کمتر و نزدیک­تر به ورودی حوضچه و همچنین حضور تیغه با ارتفاع بیشتر و دورتر از ورودی حوضچه بیشترین تاثیر را بر راندمان ته‌نشینی دارد.

کلیدواژه‌ها


عنوان مقاله [English]

Numerical Investigation of baffle effect on sedimentation anf flow field in sedimentation tank

نویسندگان [English]

  • Elham Saeedi 1
  • Ehsan Behnamtalab 2
  • Ali akbar Salehi Neyshaboury 3
1 . M.Sc. of Hydraulic Structure, Tarbiat Modares University, Tehran, Iran
2 Hakim Sabzevari University, Civil Engineering
3 Professor, Water engineering department, Tarbiat Modares University, Iran,
چکیده [English]

Sedimentation by gravity is a common, highly applicable separation method for the suspended solid particles of water and wastewater. Sedimentation basin is an important component of every water treatment process. Due to high maintenance costs of these basins, up to about 30% of all costs in a water treatment plant, optimum performance of settling basin is very significant. In order to improve the efficiency of the basin, engineers have proposed various methods, among which, “changing the geometry along with installation of baffle in the basin” is economic and has attracted the attention of researchers. In the present paper, numerical simulation was made by using Flow3D software and RNG k-ε turbulence model for a flow consisting of settlement particles in the rectangular settlement basin by a finite volume method (FVM). This study aims at numerical simulation of the hydraulic flow in settling basins with various baffle configurations, and finally, obtaining the best geometry for the baffle. Considering the relative consistency of the numerical model results and the experimental data, the numerical simulation results were validated using the Flow3D model. The results showed that the flow in the settling basin is severely affected by the baffle. According to the studied models, it is clear that the baffles installed with lower height and closer to the basin inlet and baffles with high height and far away from the basin inlet have the most effective case on the settlement efficiency.

کلیدواژه‌ها [English]

  • : settling tank
  • Baffle
  • Sedimentation
  • Vortex
  • Flow3D

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