Journal of Water and Soil Science
علوم آب و خاک
jwss
Agriculture
http://jstnar.iut.ac.ir
0
user
2476-3594
2476-5554
10.47176/jwss
fa
jalali
1397
9
1
gregorian
2018
12
1
22
4
online
1
fulltext
fa
بررسی تأثیر نوع رسوبات و تغییر فرم خروجی تخلیه کننده تحتانی با بهکارگیری سازه نیماستوانه بر حفره رسوبشویی به کمک مدل فیزیکی
Investigation of the Effect of the Kind of Sediments and the Change in the Bottom Outlet Form Using a Semi-Cylinder Structure on the Score Cone by a Physical Model
عمومی
Ggeneral
پژوهشي
Research
<div style="text-align: justify;"><strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">در روش رسوبشویی تحت فشار، زمانیکه</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">آب</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">از</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">میان</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">تخلیه</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">کنندههای</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">تحتانی خارج</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">میشود،</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">پس</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">از</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">گذشت مدت زمانی</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">از</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">انجام رسوبشویی،</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">حفرهای</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">از</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">آبشستگی</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">به</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">شکل</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">مخروط</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">در جلوی</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">دریچه</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">تحتانی بهوجود خواهد آمد که ابعاد این مخروط به پارامترهای مختلفی همچون دبی جریان خروجی، عمق آب داخل مخزن و نوع رسوبات تجمع یافته در درون مخزن بستگی دارد. در</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">این پژوهش</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">برای بررسی اثر رسوبات چسبنده و غیرچسبنده</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">بر تشکیل مخروط رسوبشویی،</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">از</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">یک مدل</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">فیزیکی با ابعاد مشخص استفاده شد و بهمنظور</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">توسعه روش تخلیه</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">رسوبات، یک</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">سازه</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">نیماستوانه</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">در</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">جلوی</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">تخلیه</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">کننده</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">تحتانی مورد</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">آزمایش</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">قرار</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">گرفت. آزمایشها در دانشگاه شهید چمران اهواز در دو حالت استفاده از نیماستوانه و بدون نیماستوانه و همچنین رسوبات چسبنده و غیرچسبنده با دبیهای مختلف و در مجموع به تعداد 90 آزمایش انجام</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">پذیرفت. نتایج</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">نشان</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">داد</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">که</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">با</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">افزایش</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">دبی،</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">بهطور</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">متوسط در دو حالت بدون نیماستوانه و با نیماستوانه</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">افزایش حجم مخروط رسوبشویی</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">را همراه دارد. با کاهش ارتفاع آب، جریان از حالت مستغرق خارج شده و به سمت فلاشینگ آزاد میرفت که در نتیجه افزایش حجم و طول مخروط را شاهد بودیم. استفاده از نیماستوانه بهطور متوسط باعث افزایش رسوبشویی شده است که این افزایش رسوبشویی بهعلت بهوجود آمدن</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">یک</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">جفت گرداب</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">چرخشی</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">در</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">داخل</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">سازه</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">نیماستوانه</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">در</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">دو طرف</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">محور</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">مرکزی</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">دریچه</span></span></strong> <strong><span style="font-family:b lotus;"><span style="font-size:11.0pt;">است.</span></span></strong></div>
<div style="text-align: justify;">In a pressure flushing method, when the water is discharged from the bottom outlet, after a period of flushing, a flushing cone will be formed at the front of the bottom outlet; the dimension of this cone is affected by several parameters such as outlet discharge flow, water depth of reservoir, and the kind of sediments accumulated in the reservoir. In this study, for the effect of cohesive & non-cohesive sediments, a physical model using specific dimensions was employed in order to develop the sediment evacuation method, and them a Semi-Cylinder structure in front of the lower drain was tested. The experiments were carried out using cohesive & non-cohesive sediments under two conditions: with the semi-cylinder and without it, at 90 experiments. The results indicated that the with discharge was increased, on i average, under both conditions and the volume of the score cone was increased. With decreasing the water depth, the flow mood was changed to free flushing, increasing the length and volume of the score cone. Semi-Cylinder form, on average, increased the volume of sedimentation and the length of sedimentation; this increase could be due to the formation of a pair of rotating Vortexes inside the Semi-Cylinder structure on both sides of the central axis of the valve.<span dir="RTL"></span></div>
رسوبات چسبنده و غیرچسبنده, رسوبشویی تحت فشار, سازه نیماستوانه, حفره رسوبشویی, جریان چرخشی
Cohesive and non-cohesive sediments, Pressure flushing, Semi-Cylinder structure, Flushing cone, Rotating Vortexes
85
98
http://jstnar.iut.ac.ir/browse.php?a_code=A-10-3675-2&slc_lang=fa&sid=1
R.
Amirjani
روزبه
امیرجانی
dr.r_am@yahoo.com