تحلیل آزمایشگاهی اثرمتقابل جریان یک‌سویه و باله بر مکانیزم خوددفنی خطوط لوله

نوع مقاله: مقاله پژوهشی

نویسندگان

1 فارغ التحصیل دکترای سازه های آبی ، پردیس بین الملل دانشگاه فردوسی مشهد

2 استاد گروه علوم و مهندسی آب، دانشکده کشاورزی، دانشگاه فردوسی مشهد

3 علوم ومهندسی آب- دانشگاه فردوسی مشهد- مشهد - ایران

چکیده

جهت تحریک خوددفنی مصنوعی لوله با هدف تأمین شرایط ایمن برای خطوط لوله انتقال در بستر فرسایش­پذیر می‌توان از صفحه نصب شده در بالای خط لوله به نام اسپویلر یا باله استفاده کرد. بررسی عملکرد اسپویلر نصب شده بر روی لوله با قابلیت جابجایی طبیعی می­تواند تفاوت عمده­ای با تحقیقات قبلی داشته باشد. در این پژوهش آزمایشگاهی به بررسی پارامتر‌های موثر بر فرآیند خوددفنی لوله پرداخته شد. رابطه‌ای جهت برآورد عمق خوددفنی در حالت نشست طبیعی لوله پیشنهاد شد و مشخص گردید جابجایی لوله عمق آبشستگی را تا 54 درصد نسبت به لوله متصل به فلوم کاهش می­دهد. با تغییر ارتفاع اسپویلر(S) بر روی لوله این نتیجه حاصل گردید که بیش­ترین مقدار خوددفنی برای نسبت S=D(D قطر لوله) بوده و میزان آن در بستر ریزدانه معادل70 درصد قطر لوله و برای بستر درشت دانه این مقدار 67 درصد قطر لوله است. طول گسترش گردابه‌های دنباله‌ای در لوله با نشست طبیعی نسبت به لوله ثابت بیش­تر بوده و با نصب اسپویلر و ازدیاد ارتفاع آن افزایش می‌یابد. بیش­ترین افزایش طول گسترش گردابه‌های دنباله‌ای در اسپویلر به ارتفاع معادل قطر لوله می‌باشد. بیش­ترین میزان دفن‌شدگی نیز در زاویه نصب صفر درجه اسپویلر نسبت به محور قایم لوله اتفاق افتاد.

کلیدواژه‌ها


عنوان مقاله [English]

Experimental analysis of the interaction between the unidirectional flow and spoiler on mechanism of self burial pipelines

نویسندگان [English]

  • jafar Mehrabadi 1
  • bijan Gahraman 2
  • kazem Esmaili 3
1 PhD graduate of hydraulic structure.,Water Eng.Dep , International Campus of Ferdowsi University of Mashhad, Mashhad, Iran
2 Professor., Department of Water Science and Engineering., Ferdowsi University of Mashhad, Mashhad, Iran
3 water science and engineering. ferdowsi university of mashhad- mashhad -Iran
چکیده [English]

To stimulate the artificial self-burial of pipelines to provide safe conditions in erodible beds, the spoiler can be used at the top of the pipeline. The study of the performance of the spoiler that mounted on the naturally moveable pipe is a major gap that not founded in previous research. In this experimental study the parameters affecting the self-burial process of the pipelines were investigated. An equation was proposed for estimating the depth of self-burial in the normal settling of the pipe and was found that the moveable pipe decrease the scour depth by 54 percent in comparison with the fixed pipe. Maximum change in self –buried was obtained at S=D (S is the length of spoiler & D is the diameter of the pipe) that was equal to 70 and 67 percent of the diameter of the pipe in fine and coarse beds, respectively. The length of Lee-wake erosion in the pipe with natural motion was greater than in which the fixed pipe and increase with installed spoiler and spoiler height increases. Maximum length of Lee-wake erosion happened when S=D. The most burying is at zero degrees of the spoiler to the vertical axis.

کلیدواژه‌ها [English]

  • pipelines
  • Self –buried
  • Spoiler
  • Transportation

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