تعیین عمق نفوذ آلاینده در بستر رودخانه‌ها به منظور ارزیابی خاصیت خودپالائی رودخانه‌ها با استخراج یک رابطه تحلیلی

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده فنی، دانشگاه مراغه، مراغه، ایران.

چکیده

در این تحقیق به منظور بررسی خاصیت خودپالائی رودخانه ­ها سعی گردید تا عمق نفوذ آلاینده­ در بستر رودخانه ­ها تعیین گردد. بدین منظور مجموعه ­ای از داده ­های آزمایشگاهی برداشت شده و یک رابطه تحلیلی برای بررسی عمق و مکانیزم نفوذ آن استخراج شد. از حسگر­های هدایت الکتریکی و ردیاب کلرید سدیم به عنوان آلاینده غیرواکنشی در انجام آزمایش ­ها استفاده شد و برای استخراج رابطه تحلیلی، ابتدا یک مدل مفهومی بر اساس روش سلول­ های ترکیبی تهیه شده و با اعمال قانون بقای جرم در یک ستون قائم از بستر رودخانه، معادله دیفرانسیل حاکم تشکیل و سپس حل گردید. نتایج آزمایشگاهی در چهارچوب رابطه استخراج شده مورد بررسی قرار گرفت و مشاهده گردید که رابطه ارائه شده به خوبی قادر به باز­سازی منحنی­ های غلظت-زمان درون بستر می­ باشد. پارامتر­های زمانی مدل نیز استخراج شد و روند تغییرات آن با سایر پارامتر­های پژوهش مورد کاوش قرار گرفت و مشاهده شد که مجموع سه پارامتر زمانی مدل ( ) رابطه معکوس با ضریب پخشیدگی عمقی داشته و همچنین مقدار آن با افزایش عمق بستر افزایش می­ یابد. از حاصل­ضرب پارامتر منفذ و سرعت منفذی به عنوان شاخصی برای تعیین ضریب پخشیدگی عمقی استفاده شد. همچنین مقادیر مربوط به پارامتر­های سرعت، ضریب پخشیدگی عمقی و انتشارپذیری نیز در اعماق مختلف بستر محاسبه شده و مشاهده شد که مقدار تمامی آن­ها با افزایش عمق بستر کاهش می ­یابد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Estimation of the Penetration Depth of the Pollution in the River Bed for Evaluation of the Self-Purification Characteristics of the Rivers by Developing a Novel Theoretical Relationship

نویسندگان [English]

  • Jafar Chabokpour
  • Bagher Dini
Civil engineering department, university of Maragheh
چکیده [English]

In the current study, it was tried to determine the mechanism of the tracer penetration through the depth of the river beds to investigate the self-purification nature of the rivers. For this purpose, experimental tests were carried out, and an analytical solution was developed. The electrical conductivity sensors and sodium chloride tracer (as a conservative contaminant) were operated in the operations. Also, for the derivation of the analytical equation, a conceptual model was presented based on the hybrid cells in the series model. Then, by imposing the mass conservation to each cell of the depth column, the governing differential equation was obtained and solved. Next, the results were evaluated by the framework of the developed equation. Moreover, the applicability of the new model was checked and confirmed by the recreation of the breakthrough curves. The time parameters of the new model were extracted. Then, their variation by the other parameters was queried. It was observed that the sum of temporal parameters () have a reverse relationship with the vertical dispersion coefficient. On the other hand, its value has been raised by an increment of the bed depth. Furthermore, the product of the void scale and the pore velocity was used for the calculation of the vertical dispersion coefficient. Also, the magnitudes of the pore velocity and dispersivity were commuted. The results revealed that by the increase of the bed depth, the mentioned parameters were decreased.

کلیدواژه‌ها [English]

  • Self-purification
  • Penetration depth of the pollution
  • River bed
  • Analytical model

مراجع

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نشریه مهندسی عمران امیرکبیر
دوره 53، شماره 5
مرداد 1400
صفحه 2117-2130

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