بررسی آزمایشگاهی عملکرد صفحات مشبک افقی در استهلاک انرژی شیب‌شکن‌های مایل

نوع مقاله : مقاله پژوهشی

نویسندگان

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

2 استادیار گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه مراغه، مراغه، ایران

3 دانشجوی کارشناسی ارشد عمران آب و سازه‌های هیدرولیکی، گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه مراغه، ایران

چکیده

در تحقیق حاضر، از صفحات مشبک افقی در لبه شیب­شکن مایل به عنوان سازه مستهلک­کننده انرژی جهت افزایش میزان استهلاک انرژی در پایین­دست استفاده شد. آزمایش­های مربوطه در سه زاویه، دو ارتفاع شیب­شکن و دو نسبت تخلخل صفحات مشبک انجام گرفت. در مجموع، 108 آزمایش متفاوت در محدوده دبی­ 200-700 لیتر در دقیقه انجام شد. نتایج نشان داد استهلاک انرژی با افزایش طول نسبی خیس شده صفحات مشبک افزایش می­یابد، به­طوری که بیشترین استهلاک انرژی در صفحه مشبک افقی با تخلخل 40 درصد رخ داد. مجهز نمودن شیب­شکن مایل به صفحات مشبک افقی، اعداد فرود پایین­دست را نیز در سه زاویه و دو نسبت تخلخل، از بازه­ 49/4 الی 35/8 به بازه 48/1 الی 78/5 کاهش داد. همچنین افزایش زاویه شیب­شکن مایل سبب افزایش عمق نسبی پایین­­دست شد، به­گونه­­­ای که شیب­شکن مایل مجهز به صفحه مشبک افقی با زاویه 45 درجه و تخلخل 40 درصدی صفحات، بهترین عملکرد در افزایش عمق نسبی پایین­دست را به خود اختصاص دادند. افزایش زاویه و تخلخل صفحات مشبک نیز باعث کاهش متوسط راندمان استهلاک انرژی می­شود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Experimental Investigation of the Performance of Horizontal Screen on Energy Dissipation in Inclined Drop

نویسندگان [English]

  • Rasoul Daneshfaraz 1
  • Mahdi Majedi Asl 2
  • Ali Bazyar 3
1 Associate Professor, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran.
2 Assistant Professor, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran.
3 M.Sc. Student, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran
چکیده [English]

In the present study, horizontal screens at brink of inclined drop were used as an energy dissipater structure to increase the downstream energy dissipation. The experiments were carried out in three angles of drop, two drop heights, and two porosity ratios of horizontal screen. In total, 108 experiments were performed in discharge range of 200–700 L/min. The results showed that the energy dissipation increases with increasing relative wetting length of the screen, such a way that the highest energy dissipation occurs in the horizontal screen with a porosity of 40%. Inclined drop equipped with horizontal screen reduced downstream Froude numbers in three angles of drop and two porosity ratios from a range of 4.49 - 8.35 to a range of 1.48 - 5.78. Also, increasing the angle of drop increases the relative depth of downstream, so that the drop angle of 45 ° and screen porosity of 40% had the best performance in increasing the relative depth of downstream. Increasing the drop angle and screen porosity also reduces the average efficiency of energy dissipation.

کلیدواژه‌ها [English]

  • energy dissipation
  • horizontal screen
  • inclined drop
  • relative wetted length
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