بررسی عددی پارامترهای موثر بر هیدرولیک جریان در سرریزهای تناسبی دودکشی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استاد، گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه مراغه

2 دانش آموخته دکتری، گروه مهندسی آب، دانشکده کشاورزی، دانشگاه تبریز، تبریز، ایران

3 دانشجوی آب و سازه های هیدرولیکی . دانشکده فنی و مهندسی، دانشگاه مراغه

چکیده

سرریزهای تناسبی به­­دلیل تأمین دقت مورد نیاز در برآورد میزان دبی از اهمیت بالایی در اندازه­گیری جریان برخوردار هستند. در این مطالعه، با استفاده از نرم­افزار FLOW-3D پارامترهای هیدرولیکی از جمله توزیع سرعت و بردارهای سرعت، توزیع فشار سیال در کانال و سرریز، عدد فرود، نمودار دبی-اشل و ضریب­دبی سرریزهای دودکشی با زوایای (زاویه قسمت مثلثی سرریز با دیواره قائم) ˚37، ˚42، ˚2/47 و ˚53 در محدوده دبی 2 الی 9 لیتر بر ثانیه مورد بررسی قرار گرفته است. در تحقیق حاضر مدل آشفتگی RNG در مقایسه با مدل­های آشفتگی LES، k-ε و k-ω به­علت مقادیر کم درصد خطای نسبی و خطای مطلق انتخاب شد. نتایج نشان داد که با افزایش زاویه، در بار آبی یکسان، میزان دبی و عدد فرود کاهش و با افزایش بار آبی بالای تاج سرریز، عدد فرود افزایش پیدا می­کند. همچنین براساس نتایج حل عددی با کاهش زاویه، سرعت متوسط جریان در بالادست سرریز افزایش می­یابد. در این مطالعه، براساس پارامترهای بی­بعد رابطه چند جمله­ای غیرخطی با تلفیق داده­های تمامی سرریزهای مدل شده برای پیش­بینی ضریب­دبی به­دست آمد. مقایسه نتایج آزمایشگاهی و حل عددی با رابطه پیشنهادی در تحقیق حاضر، حاکی از دقت بالای معادله ارائه شده می­باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Numerical Investigation on Effective Parameters on Hydraulic Flows in Chimney Proportional Weirs

نویسندگان [English]

  • Rasoul Daneshfaraz 1
  • Reza Norouzi 2
  • Hamidreza Abbaszadeh 3
1 Professor , Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Iran.
2 Ph.D., Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz, Iran.
3 M.Sc. Student, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran
چکیده [English]

Proportional weirs are of great importance in flow measurement due to providing the required accuracy in estimating the flow rate. In this study, the hydraulic parameters such as velocity distribution and velocity vectors, fluid pressure distribution in channel and weir, Froude number, stage-discharge diagram and discharge coefficient of chimney weirs with angles (The angle of triangular part of weir with the vertical wall) of 37˚, 42˚, 47.2˚ and 53˚ in the range of 2 to 9 liters per second was investigated using FLOW-3D software. In the present study, the RNG turbulence model was selected in comparison with the LES, k-ε and k-ω turbulence models due to low values ​​of relative error percentage and absolute error. The results showed that by increasing angle, at the same water head, the flow rate and Froude number decreases, and by increasing water head above the weir crest, the Froude number increases. Also, based on the results of numerical solution, by decreasing angle, the upstream mean velocity increases. In this study, based on dimensionless parameters, a nonlinear polynomial equation was obtained by combining the data of all modeled weirs to predict the discharge coefficient. Comparing the results of experimental and numerical solution with the presented equation indicates the high accuracy of the presented equation.

کلیدواژه‌ها [English]

  • Chimney weir
  • water head
  • Froude number
  • Velocity distribution
  • discharge coefficient
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