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شبیهسازی عددی استهلاک انرژی در مواجهه با انقباض هلالیشکل مسیر جریان | ||
| تحقیقات آب و خاک ایران | ||
| دوره 52، شماره 5 - شماره پیاپی 65، مرداد 1400، صفحه 1299-1314 اصل مقاله (1.77 M) | ||
| نوع مقاله: مقاله پژوهشی | ||
| شناسه دیجیتال (DOI): 10.22059/ijswr.2021.318989.668895 | ||
| نویسندگان | ||
| رسول دانشفراز* 1؛ احسان امین وش2؛ حمیدرضا عباس زاده3 | ||
| 1استاد، گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه مراغه | ||
| 2گروه عمران، دانشکده فنی و مهندسی، دانشگاه مراغه، مراغه، ایران | ||
| 3دانشجوی کارشناسی ارشد گروه عمران آب و سازه های هیدرولیکی، دانشکده فنی و مهندسی، دانشگاه مراغه، مراغه، ایران | ||
| چکیده | ||
| از روشهای کنترل و کاهش انرژی جریان، استفاده از سازههای مستهلککننده انرژی و تشکیل پرش هیدرولیکی است. یکی از انواع این سازهها، المانهای تنگشدگی در مسیر جریان است که منجر به افت انرژی جریان عبوری میشود. در تحقیق حاضر به بررسی عددی تأثیر تنگشدگی هلالیشکل بهعنوان سازه مستهلککننده انرژی در مسیر جریان فوقبحرانی با استفاده از نرم‌افزار FLOW-3D پرداخته شده است. با بررسی نتایج حاصل از شبیهسازی، مدل آشفتگی RNG بهعلت برخورداری از دقت بیشتر و پائین‌بودن درصد خطای نسبی و خطای مطلق نسبت بهسایر مدلها، از میان 4 مدل آشفتگی RNG، k-ε، k-ω و LES انتخاب شد. در این مطالعه، دامنه عدد فرود بعد از دریچه بهعنوان موثرترین پارامتر بدونبعد در استهلاک انرژی از 8/2 تا 5/7 تغییر کرده و مقادیر تنگشدگی از طرفین 5 و 5/7 سانتیمتر میباشد. نتایج حاکی از آن است که در تمامی حالات استفاده از تنگشدگی هلالیشکل، استهلاک انرژی ناشی از تنگشدگی بهترتیب در تنگشدگی 5 و 5/7 سانتیمتر براساس افت انرژی نسبت به بالادست 62/24% و 84/29% و نسبت به پائیندست 14/46% و 42/48% بیشتر از پرش کلاسیک آزاد است. هم‌چنین با بررسی نتایج بهدست آمده مشاهده شد که تنگشدگی هلالیشکل در مقایسه با انقباض ناگهانی، حاصل از مطالعات محققین پیشین، عملکرد بهتری از نظر میزان افت انرژی دارد. براساس نتایج حاصل از شبیهسازی با افزایش عدد فرود بالادست، افت انرژی نسبت به بالادست و پائیندست تنگشدگی هلالیشکل افزایش یافته به‌طوری‌که استفاده از المانهای تنگشدگی باعث کاهش عدد فرود در پائیندست مقطع تنگشدگی در بازه 6/1 الی 3/2 شده است. | ||
| کلیدواژه‌ها | ||
| استهلاک انرژی؛ تنگ شدگی هلالی؛ عدد فرود؛ پرش هیدرولیکی؛ مدل آشفتگی | ||
| عنوان مقاله [English] | ||
| Numerical Simulation of Energy Dissipation in Crescent-Shaped Contraction of the Flow Path | ||
| نویسندگان [English] | ||
| Rasoul Daneshfaraz1؛ Ehsan Aminvash2؛ Hamidreza Abbaszadeh3 | ||
| 1Professor, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Iran. | ||
| 2M.sc student, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Iran. | ||
| 3M.sc student, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Iran | ||
| چکیده [English] | ||
| One of the methods of controlling and reducing flow energy is to use energy dissipating structures through formation of hydraulic jumps. One of these types of structures is the constriction elements in the flow path, which leads to a decrease in the energy of the passing flow. In the present study, the effect of crescent-shaped contraction as an energy dissipating structure in the supercritical flow path has been investigated using FLOW-3D software. Examining the simulation results, the RNG model among the four turbulence models, RNG, k-ε, k-ω and LES was selected due to its higher accuracy and lower relative error and absolute error percentage. In this study, the amplitude of the Froude number after the gate as the most effective dimensionless parameter in energy dissipation varied from 2.8 to 7.5 and the values of stenosis on both sides are 5 and 7.5 cm. The results show that in all cases of using the crescent-shaped contractions, the energy dissapation in 5 and 7.5 cm contractions are respectively 24.62% and 29.84% more than the ones in the classic free jump, based on the energy drop relative to the upstream, and 46.14% and 48.42% more, based on the energy drop relative to the downstream. Also, by reviewing the previous researchs, it was found that the crescent-shaped contractions have a better performance in terms of energy loss compared to the sudden contraction. Based on the simulation results, with increasing the upstream Froude number, the energy dissipation is increased relative to the upstream and downstream of crescent-shaped contraction, so that the use of contraction elements reduces the downstream Froude number of the contracted section in the range of 1.6 to 3/2. | ||
| کلیدواژه‌ها [English] | ||
| Energy dissipation, Crescent-shaped contraction, Froude number, Hydraulic jump, Turbulence model | ||
| مراجع | ||
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