مطالعه آزمایشگاهی و عددی نشت در روزنه‌های لوله‌های پلی‌اتیلن
محورهای موضوعی : آب و محیط زیست
سید علی صدرالساداتی
1
(دانش‌آموخته دکتری، مهندسی محیط زیست-آب و فاضلاب، دانشکده عمران، آب و محیط زیست، دانشگاه شهید بهشتی)
محمدرضا جلیلی قاضی زاده
2
(دانشیار دانشکده عمران، آب و محیط زیست، دانشگاه شهید بهشتی)
کلید واژه: شبکه توزیع آب, روزنه, نشت, لوله پلی‌اتیلن چگالی بالا, رابطه نشت-فشار,
چکیده مقاله :
زمینه و هدف: یکی از مؤثرترین روش‌های مقابله با نشت در شبکه‌های توزیع آب، مدیریت فشار می‌باشد و لذا درک صحیح از رفتار نشت و رابطه آن با تغییرات فشار می‌تواند نقش بسزایی در کنترل تلفات داشته باشد. استفاده از لوله‌های پلی‌اتیلن چگالی بالا (HDPE) در سال‌های اخیر در شبکه‌های توزیع آب بسیار افزایش یافته و در برخی روستاها و شهرهای کوچک به صورت کامل از این نوع لوله‌ها استفاده شده است. هدف از این مطالعه شناخت رفتار نشت از روزنه‌ها در لوله‌های پلی‌اتیلن می‌باشد. روش بررسی: در مطالعه حاضر رفتار نشت روزنه‌ای در لوله‌های پلی‌اتیلن به صورت آزمایشگاهی و عددی بررسی شده است. در این مطالعه تأثیر پارامتر دما به عنوان یکی از عوامل اصلی بر رفتار نشت مورد مطالعه قرار گرفته است. یافته‌ها: نتایج به دست آمده نشان داد استفاده از رابطه کلاسیک توریچلی برای روزنه کاربرد دارد و مقدار توان نشت برای روزنه‌ها تقریباً 5/0 می‌باشد. در این مطالعه همچنین نشان داده شد ضریب تخلیه جریان خروجی از روزنه به عواملی نظیر عدد رینولدز، ضخامت جداره لوله، قطر روزنه، محیط پیرامونی و تغییر شکل روزنه وابسته است. بحث و نتیجه‌گیری: با افزایش فشار، فرض عدم تغییر شکل برای روزنه در لوله‌های پلی‌اتیلن به خصوص در دمای بالا الزاماً صادق نیست. روزنه در لوله‌هایی با الاستیسیته پایین با توجه به نوع توزیع تنش در محل بازشدگی و همچنین تأثیر ضریب پواسون با افزایش فشار از حالت تقارن خارج شده و در نتیجه باعث کاهش ضریب تخلیه می‌گردد.
Background and Objective: One of the most effective methods of coping with leakage in water distribution networks is pressure management. Therefore, a proper understanding of leakage behavior and its relationship with pressure variations can play a significant role in water loss control. The use of high-density polyethylene (HDPE) pipes has increased in recent years in water distribution networks so that in some rural area and small cities, these pipes have been utilized only. The aim of this study is to investigate the leakage behavior of orifices in HDPE pipes. Method: In the present study, the leakage behavior of polyethylene pipes has been investigated numerically and experimentally. In this study, the effect of temperature as one of the main factors on leakage behavior has been considered. Findings: The results showed that the Torricelli's classic relationship for the orifices can be used and the amount of leakage exponent for the orifices is approximately 0.5. This study shows that the discharge coefficient of the outflow from the orifices is dependent on some parameters such as Reynolds number, the thickness of pipe wall, orifice diameter, surrounding environment and orifice deformation. Discussion and Conclusion: The assumption of no deformation for the orifices in HDPE pipes with increasing pressure, particularly at high temperatures, is not necessary true. The symmetry state of the orifices in low-elastic pipes is removed with the pressure increase, due to the distribution of stress at the opening and also the effect of the Poisson coefficient, thereby reducing the discharge coefficient.
- Lambert A. 1997. Pressure management/leakage relationships: Theory, concepts and practical applications. proceeding of minimizing leakage in water supply/distribution systems, IQPC Seminar, London.
- May J.1994. Pressure dependent leakage. World Water and Environmental Engineering.
- Lambert A. 2001. What do we know about pressure-leakage relationships in distribution systems. IWA Conf n Systems approach to leakage control and water distribution system management;Citeseer.
- Van Zyl J, Clayton C.2007. The effect of pressure on leakage in water distribution systems. Proceedings of the Institution of Civil Engineers-Water Management: Thomas Telford Ltd.
- Cassa A, Van Zyl J, Laubscher R. 2010. A numerical investigation into the effect of pressure on holes and cracks in water supply pipes. Urban Water Journal.7(2):109-20.
- Walski T, Whitman B, Baron M, Gerloff F, 2009. Pressure vs. flow relationship for pipe leaks. World Environmental and Water Resources Congress: Great Rivers.
- Greyvenstein B, Van Zyl J. 2007. An experimental investigation into the pressure-leakage relationship of some failed water pipes. Journal of Water Supply: Research and Technology-AQUA.56(2):117-24.
- Hiki S. 1981. Relationship between leakage and pressure. Journal of Japan Waterworks Association.1(982):5.
- Van Zyl J, Malde R. 2017. Evaluating the pressure-leakage behaviour of leaks in water pipes. Journal of Water Supply: Research and Technology-Aqua.jws2017136.
- Coetzer A, Van Zyl J, Clayton C, 2006. An experimental investigation into the turbulent-flow hydraulics of small circular holes in plastic pipes. Water Distribution Systems Analysis Symposium.
- Schwaller J, van Zyl J. 2014. Modeling the pressure-leakage response of water distribution systems based on individual leak behavior. Journal of Hydraulic Engineering.141(5):04014089.
- Idelchik, I., Handbook of hydraulic resistance. Hemisphere, New York. 1986. 640.
- Malde R. 2015. An analysis of leakage parameters of individual leaks on a pressure pipeline through the development and application of a standard procedure: University of Cape Town.
- Novak P, Moffat A, Nalluri C, Narayanan R. 2007. Hydraulic structures: CRC Press.
- Thomas JT. 1986. Orifice Plates for Furrow Flow Measurement: Part I - Calibration.
- Fox S, Collins R, Boxall J. 2016. Physical investigation into the significance of ground conditions on dynamic leakage behaviour. Journal of Water Supply: Research and Technology-Aqua.;65(2):103-15.
- Van Zyl J, Lambert A, Collins R. 2017. Realistic Modeling of Leakage and Intrusion Flows through Leak Openings in Pipes. Journal of Hydraulic Engineering.143(9):04017030.
- Krushelnitzky R, Brachman R. 2013. Buried high-density polyethylene pipe deflections at elevated temperatures. Geotextiles and Geomembranes.40:69-77.
- Sadr-Al-Sadati, Syed Ali, and Mohammadreza Jalili Ghazizadeh. "The experimental and numerical study of water leakage from High-Density Polyethylene pipes at elevated temperatures." Polymer Testing 74 (2019): 274-280.
- The Plastics Pipe Institute(PPI). 2008. The Plastics Pipe Institute Handbook of Polyethylene Pipe Second Edition: Irving, Texas.
- Coetzer AJ, Van Zyl J, Clayton C.2006. Experimental study of the hydraulics of small circular holes in water pipes. Proceedings of the 8th Annual Symposium on Water Distribution Systems Analysis Symposium, Cincinnati, Ohio.
- Franchini M, Lanza L. Leakages in pipes: generalizing Torricelli's equation to deal with different elastic materials, diameters and orifice shape and dimensions. Urban Water Journal. 2014;11(8):678-95.
- Shahangian S.A.R, Tabesh M, Mirabi M.H. Numerical study of leakage from submerged steel pipes based on laboratory results of non-submerged pipes. Journal of Hydraulics. 2017; 11 (4): 44-29(In Persian).
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- Lambert A. 1997. Pressure management/leakage relationships: Theory, concepts and practical applications. proceeding of minimizing leakage in water supply/distribution systems, IQPC Seminar, London.
- May J.1994. Pressure dependent leakage. World Water and Environmental Engineering.
- Lambert A. 2001. What do we know about pressure-leakage relationships in distribution systems. IWA Conf n Systems approach to leakage control and water distribution system management;Citeseer.
- Van Zyl J, Clayton C.2007. The effect of pressure on leakage in water distribution systems. Proceedings of the Institution of Civil Engineers-Water Management: Thomas Telford Ltd.
- Cassa A, Van Zyl J, Laubscher R. 2010. A numerical investigation into the effect of pressure on holes and cracks in water supply pipes. Urban Water Journal.7(2):109-20.
- Walski T, Whitman B, Baron M, Gerloff F, 2009. Pressure vs. flow relationship for pipe leaks. World Environmental and Water Resources Congress: Great Rivers.
- Greyvenstein B, Van Zyl J. 2007. An experimental investigation into the pressure-leakage relationship of some failed water pipes. Journal of Water Supply: Research and Technology-AQUA.56(2):117-24.
- Hiki S. 1981. Relationship between leakage and pressure. Journal of Japan Waterworks Association.1(982):5.
- Van Zyl J, Malde R. 2017. Evaluating the pressure-leakage behaviour of leaks in water pipes. Journal of Water Supply: Research and Technology-Aqua.jws2017136.
- Coetzer A, Van Zyl J, Clayton C, 2006. An experimental investigation into the turbulent-flow hydraulics of small circular holes in plastic pipes. Water Distribution Systems Analysis Symposium.
- Schwaller J, van Zyl J. 2014. Modeling the pressure-leakage response of water distribution systems based on individual leak behavior. Journal of Hydraulic Engineering.141(5):04014089.
- Idelchik, I., Handbook of hydraulic resistance. Hemisphere, New York. 1986. 640.
- Malde R. 2015. An analysis of leakage parameters of individual leaks on a pressure pipeline through the development and application of a standard procedure: University of Cape Town.
- Novak P, Moffat A, Nalluri C, Narayanan R. 2007. Hydraulic structures: CRC Press.
- Thomas JT. 1986. Orifice Plates for Furrow Flow Measurement: Part I - Calibration.
- Fox S, Collins R, Boxall J. 2016. Physical investigation into the significance of ground conditions on dynamic leakage behaviour. Journal of Water Supply: Research and Technology-Aqua.;65(2):103-15.
- Van Zyl J, Lambert A, Collins R. 2017. Realistic Modeling of Leakage and Intrusion Flows through Leak Openings in Pipes. Journal of Hydraulic Engineering.143(9):04017030.
- Krushelnitzky R, Brachman R. 2013. Buried high-density polyethylene pipe deflections at elevated temperatures. Geotextiles and Geomembranes.40:69-77.
- Sadr-Al-Sadati, Syed Ali, and Mohammadreza Jalili Ghazizadeh. "The experimental and numerical study of water leakage from High-Density Polyethylene pipes at elevated temperatures." Polymer Testing 74 (2019): 274-280.
- The Plastics Pipe Institute(PPI). 2008. The Plastics Pipe Institute Handbook of Polyethylene Pipe Second Edition: Irving, Texas.
- Coetzer AJ, Van Zyl J, Clayton C.2006. Experimental study of the hydraulics of small circular holes in water pipes. Proceedings of the 8th Annual Symposium on Water Distribution Systems Analysis Symposium, Cincinnati, Ohio.
- Franchini M, Lanza L. Leakages in pipes: generalizing Torricelli's equation to deal with different elastic materials, diameters and orifice shape and dimensions. Urban Water Journal. 2014;11(8):678-95.
- Shahangian S.A.R, Tabesh M, Mirabi M.H. Numerical study of leakage from submerged steel pipes based on laboratory results of non-submerged pipes. Journal of Hydraulics. 2017; 11 (4): 44-29(In Persian).