شبیه سازی تاثیر تغییرات فشار محیط بر عملکرد جداکننده دو مرحله ای واسطه سنگین آزمایشگاهی

دهقان, رضا; آقایی, محسن

doi:10.30479/jmre.2019.10142.1232

شبیه سازی تاثیر تغییرات فشار محیط بر عملکرد جداکننده دو مرحله ای واسطه سنگین آزمایشگاهی

نوع مقاله : علمی-پژوهشی

نویسندگان

¹ استادیار، دانشکده مهندسی معدن و متالورژی، دانشگاه یزد، یزد

² دانشجوی دکترا، دانشکده مهندسی معدن و متالورژی، دانشگاه یزد، یزد

10.30479/jmre.2019.10142.1232

چکیده

از آنجا که در جداکننده دو مرحله‌ای واسطه سنگین، بار ورودی تحت فشار اتمسفر به دستگاه وارد می‌شود و اختلاف فشار سیال داخل دستگاه با محیط بیرون، از طریق تنظیم فشار معکوس در خروجی‌های غوطه‌ور و محصول میانی کنترل می‌شود، بررسی تاثیر فشار محیط بر عملکرد جداکننده اهمیت دارد. در این تحقیق، اثر فشار محیط بر الگوی جریان در این جداکننده با استفاده از دینامیک سیالات محاسباتی (CFD) مدلسازی شده است. بدین منظور، از مدل چندفازی حجم سیال (VOF) برای تعیین شکل اولیه و موقعیت هسته هوا در داخل جداکننده و از مدل فاز مجزا (DPM) برای توصیف جریان ذرات جامد استفاده شد. آشفتگی با استفاده از مدل تنش رینولدز (RSM) توصیف شده است. شبیه‌سازی در فشار 1 اتمسفر(در سطح آب‌های آزاد )، 86/0 اتمسفر (در ارتفاع 1250 متر از سطح دریا) و 64/0 اتمسفر (در ارتفاع 3500 متر از سطح دریا) انجام شد. بر اساس نتایج شبیه‌سازی، تغییر در فشار محیطی منجر به تغییراتی در میدان جریان، پارامترهای ماکروسکوپیک و عملکرد جداکننده می‌شود. اعتبار نتایج شبیه‌سازی با مقایسه و انطباق بر نتایج آزمایشگاهی حاصل از یک دستگاه جداکننده شفاف ساخته شده به همین منظور تائید شده است. نتایج تحقیق حاضر نشان داد که با کاهش فشار محیط، مقدار خطای احتمال (Ep) کاهش و بازیابی واسطه افزایش می‌یابد، اما مقادیر این تاثیرات کمتر از 2 % به دست آمد. لذا می‌توان از جداکننده واسطه سنگین گریز از مرکز دو مرحله‌ای در موقعیت‌های مکانی با ارتفاع مختلف از سطح دریا بدون این که خللی در عملکرد جداکننده ایجاد شود، استفاده نمود.

کلیدواژه‌ها

عنوان مقاله [English]

Simulation of the Effect of Atmospheric Pressure on the Performance of Laboratory Two-Stage Dense Medium Separator

نویسندگان [English]

R. Dehghan ¹
M. Aghaei ²

¹ Assistant Professor, Dept. of Mining and Metallurgical Engineering, Yazd University, Yazd, Iran

² Ph.D Student, Dept. of Mining and Metallurgical Engineering, Yazd University, Yazd, Iran

چکیده [English]

The effects of atmospheric pressure of the site of installation of a centrifugal two-stage heavy medium separator is of crucial importance because the pressure difference between the medium input and the sink output streams is adjusted by the back pressure rings. However, contrary to the dense medium cyclone, the raw feed ore into this separator is sluiced without pumping. In this research, the effect of atmospheric pressure on the flow pattern inside the Tri-Flo separator is investigated using the computaional fluid dynamic (CFD) simulation. Therefore, the volume of fluid (VOF) model and discrete phase model (DPM) were used for the calculation of the diameter of the air core and the behavior of solid particles, respectively. Reynols stress model (RSM) was used for turbulence modeling. Simulations were performed in three different atmospheric pressure including 1, 0.86 and 0.64 atm, representing the site of installation at sea level and heights of 1250 meters and 3500 meters above the sea level, respectively. The CFD simulation results showed that the change in atmospheric pressure has some effects on the flow fields, macroscopic parameters and the performance of the Tri-Flo separator. The results of simulation were validated against the experimental data achived using the transparent laboratort Tri-Flo separator. The fluid velocity in output streams and the size and the pattern of air core were used for validation. The decrease in Ecart propale error (Ep) of the separator and increase in the medium recovery were observed, when the atmospheric pressure was decreased. However, the effects were in the margin of 2%. According to the results of this research, the Tri-Flo separator can be used in different elevations from the sea level, without serious problem in the operation regime.

کلیدواژه‌ها [English]

CFD simulation
Atmospheric pressure
Discrete phase model (DPM)
Dense medium separation (DMS)

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