ارائه شاخص قابلیت اطمینان جدید برای ارزیابی عملکرد شبکه توزیع آب

نوع مقاله: مقاله پژوهشی

نویسندگان

1 استادیار، گروه مهندسی عمران، دانشگاه شهید مدنی آذربایجان، تبریز، ایران

2 استاد دانشکده مهندسی عمران و عضو قطب علمی مهندسی و مدیریت زیرساخت‌های عمرانی، پردیس دانشکده‌های فنی، دانشگاه تهران، تهران، ایران

چکیده

در سـال‌هـای اخیـر شاخص‌های قابلیت اطمینان زیادی به‌منظور بررسی شبکه‌های آبی توسط پژوهشگران مختلف تعریف شده است، به‌طوری که کاربران و مدیران به‌دلیل پیچیدگی، تعدد و دامنه تغییرات ناهمگون نتایج برای شاخص‌ها، در به‌کارگیری آنها دچار سردرگمی هستند. در این پژوهش با در نظر گرفتن ویژگی‌های یک شاخص کاربردی که شامل نرمال بودن نتایج شاخص، حساسیت مناسب شاخص نسبت به تغییرات پارامترهای شبکه، تغییر جهت مناسب شاخص در شرایط حدی و قابلیت شاخص در پوشش شرایط بحرانی بهره‌برداری است، شاخص‌های قابلیت اطمینان هیدرولیکی و کیفی جدیدی ارائه شد. برای این منظور ضوابط و معیارهای طراحی و بهره‌برداری شبکه‌های توزیع آب به‌صورت کنترل حدود تغییرات حداقل و حداکثر و بهینه فشار در گره‌ها، سرعت جریان در لوله‌ها و کلر آزاد باقیمانده در گره‌ها در نظر گرفته شد و شاخص قابلیت اطمینان فشار گرهی، شاخص قابلیت اطمینان سرعت جریان لوله‌ای، شاخص قابلیت اطمینان کیفی گرهی و شاخص قابلیت اطمینان کل شبکه تعریف شد. برای ارزیابی عملکرد شاخص‌ تعریف شده، از یک شبکه نمونه دوحلقه‌ای و یک شبکه واقعی توزیع آب استفاده شد. بررسی مقادیر شاخص‌ها نشان داد که مقدار شاخص‌ها بین 11/0 و 0/1 در نوسان است و این تغییر نشان دهنده نرمال بودن و حساسیت مناسب شاخص‌ها است. همچنین با افزایش مقادیر هد و کلر باقیمانده مخزن، شاخص‌ قابلیت اطمینان تلفیقی شبکه‌ای از 54/0 به 75/0 افزایش یافته و سپس به 54/0 کاهش یافت و این تغییر نشان‌دهنده تغییر جهت مناسب شاخص در شرایط حدی است. همچنین با شکست برخی اجزای شبکه، مقدار شاخص‌ها تغییر محسوسی نکرد و این نشان‌دهنده قابلیت شاخص‌ها در پوشش شرایط بحرانی است. با نتایج حاصل از این پژوهش مشخص شد که در مجموع شاخص‌های تعریف شده از کارایی مناسبی برای ارزیابی عملکرد شبکه‌های توزیع آب برخوردار هستند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

A New Reliability Index for Evaluating the Performance of Water Distribution Network

نویسندگان [English]

  • Mehdi Dini 1
  • Massoud Tabesh 2
1 Assist. Prof., Department of Civil Engineering, Shahid Madani University of Azarbayjan, Tabriz, Iran
2 Prof., Center of Excellence on Engineering and Management of Civil Infrastructure, School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran
چکیده [English]

Various reliability indices have been defined by researchers for the water distribution networks. Due to the complexity and heterogeneous nature of distribution networks, results of indicies can vary substantially and municipalities have hard time to select the most practical indicies for their networks.  This study was undertaken to develop a new method for identifying the best reliability index by considering various factors including the appropriate sensitivity to changes in network parameters, the appropriate shift in extreme conditions, the capability in covering critical condition, hydraulic condition, and water quality reliability. To accomplish the objective of the study, several water distribution networks were evaluated under multiple scenarios and the optimum reliability indices were verified with an example real water distribution network in Ahar. Controlling parameters included in scenario analysis for network reliability indices include: minimum, maximum and optimal pressure, residual chlorine in nodes, velocity in pipes, nodal pressure reliability, pipe velocity reliability, and nodal residual chlorine reliability . To evaluate the performance of defined index, a two-loop test (critical) were compared with the conventional single-lop test (normal). The performance assessment of indices obtained from this study showed that the index values ranged between 0.11 and 1.0, which indicate the normality and the appropriate sensitivity of the indices. Also, by increasing the residual chlorine of the reservoir, the network reliability index changed from 0.54 to 0.75 and then as the residual chlorine decreases in the distributon network the reliability index decreased back to 0.54. This appropriate shift in reliability index while changing residual chlorine in the network, cearly shows the the effectiveness of new method in determining the reliability indicies under extreme conditions. Also, the new method did not respond to the failure of some network components, as were evident with insignificant change in the indices values under critical conditions. From the results of this study generally can be concluded that the newly defined relability indices is an efficient way for evaluating the performance of water distribution networks.

کلیدواژه‌ها [English]

  • Reliability Index
  • Nodal Pressure
  • Pipe Velocity
  • Nodal Residual Chlorine
  • Water Distribution Network
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