مهندسی مکانیک مدرس

مهندسی مکانیک مدرس

اثر مدل‌های آشفتگی در شبیه‌سازی عددی جداکننده دو مرحله‌ای گریز از مرکز

نوع مقاله : پژوهشی اصیل

نویسندگان
دانشکده مهندسی معدن و متالورژی، دانشگاه یزد، یزد، ایران
چکیده
جداکننده‌های دو مرحله‌ای گریز از مرکز، جدیدترین نسل جداکننده‌های ثقلی مورد استفاده در پرعیارسازی و جدایش مواد معدنی هستند. روش‌های پرعیارسازی ثقلی روش‌هایی هستند که به وسیله آنها می‌توان مخلوطی از ذرات با ابعاد، شکل و جرم مخصوص مختلف را به کمک نیروی ثقل، نیروی گریز از مرکز و دیگر نیروها به کمک جریان سیال به خصوص آب (یا هوا) از یکدیگر جدا ساخت. جریان داخل این جداکننده‌ها همواره آشفته است. در شبیه‌سازی‌های عددی، انتخاب مدل آشفتگی مناسب از جنبه‌های مهم و کلیدی برای پیش‌بینی دقیق الگوی جریان سیال است. هدف از این مقاله یافتن مدل آشفتگی مناسب برای پیش‌بینی‌های هیدرودینامیکی در جداکننده دو مرحله‌ای گریز از مرکز به روش دینامیک سیالات محاسباتی است. بدین منظور شبیه‌سازی سه فازی جداکننده دو مرحله‌ای گریز از مرکز با استفاده از مدل‌های k-e، RNG k-e و RSM انجام شده است. ارزیابی اثر مدل آشفتگی بر میدان جریان با توجه به الگوی هسته هوا، توزیع سرعت و توزیع ذرات جامد بین جریان‌های مختلف جداکننده انجام شده است. در پایان نتایج حاصل از شبیه‌سازی CFD دستگاه با قطر ۷۰میلی‌متر با داده‌های آزمایشگاهی و تجربی اعتبارسنجی شد. درصد اختلاف نتایج شبیه‌سازی با استفاده از مدل آشفتگی RSM با نتایج تجربی در مورد بازیابی حجمی سیال و قطر هسته هوا در مراحل اول و دوم به ترتیب ۴/۷۳%،۴/۳% و ۵/۲% بود. نتایج حاصل از شبیه‌سازی با مدل‌های آشفتگی k-e، RNG k-e انطباق خوبی با نتایج تجربی نداشت.
کلیدواژه‌ها

موضوعات


عنوان مقاله English

Effect of Turbulence Models on Numerical Simulation of a Two-Stage Centrifugal Separator

نویسندگان English

M. Aghaei
R. Dehghan
Mining & Metallurgical Engineering Department, Yazd University, Yazd, Iran
چکیده English

Two-stage centrifugal separators are the last generation of gravity separators for the separation and upgrading of minerals. Gravity upgrading techniques are methods by which a mixture of particles with different dimensions, shapes, and masses can be separated by gravity, centrifugal force, and other forces by the flow of fluid, especially water (or air). The fluid flow inside such separators is always turbulent. The selection of a suitable turbulence model is an important stage for the prediction of the fluid flow pattern in numerical simulation. The purpose of this research was to find the suitable turbulence model for the prediction of hydrodynamic parameters in a two-stage centrifugal separator using computational fluid dynamics (CFD) modeling. For this purpose, multiphase simulation of the separator has been performed using five turbulence model including k-e, renormalization group (RNG k-e) and Reynolds stress model (RSM). Air core pattern, velocity distribution and partition curve of discrete phase were used for evaluation of the effect of turbulence model on the flow field. The results of the CFD simulation were validated using experimental data. The difference between the results of RSM simulation with the experimental results for fluid recovery, air-core size in the first and second stage of separator were 4.73%, 4.3% and 5.2%, respectively. The results of turbulence models of k-e and RNG k-e were not in accordance with the experimental results.

کلیدواژه‌ها English

Two-Stage Centrifugal Separator
Turbulence model
Air Core
computational fluid dynamics (CFD)
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