مهندسی مکانیک مدرس

مهندسی مکانیک مدرس

مدلسازی عددی نرخ رسوب آسفالتین در جریان آشفته ی داخل لوله مبدل های حرارتی

نویسندگان
1 دانشکده مهندسی مکانیک، دانشگاه تربیت مدرس، تهران
2 استادیار، دانشکده مهندسی مکانیک، دانشگاه تربیت مدرس
3 استادیار دانشگاه تربیت مدرس
چکیده
در این پژوهش رسوب ذرات آسفالتین در نفت خام مدلسازی شده است. فرض شده است پدیده‌ی رسوب‌گذاری شامل دو مرحله است: انتقال ذرات آسفالتین به نزدیک سطح و اتصال این ذرات به سطح. باتوجه به اندازه‌ی میکرومتری ذرات آسفالتین از نگرش گونه برای مدلسازی انتقال و اتصال ذرات آسفالتین استفاده شده است. مدلسازی انتقال ذرات آسفالتین به نزدیک سطح توسط پخش ناشی از آشفتگی جریان و حرکات براونی ذرات، انجام شده است. فرآیند اتصال نیز توسط یک واکنش شیمیایی سطحی مرتبه اول مدلسازی شده است. همچنین در مدلسازی انجام شده، اثرات شرایط عملیاتی مانند دمای سطح و سرعت در نرخ اتصال ذرات در نظر گرفته شده است. درنهایت تاثیر متغیرهای سرعت، دمای سطح و غلظت ذرات آسفالتین بر نرخ رسوب‌گذاری مدلسازی شده است و با داده‌های آزمایشگاهی مقایسه شده است. روند نتایج حاصل به ‌خوبی با داده‌های آزمایشگاهی تطابق دارد بطوریکه بیشترین مقدار خطای مدلسازی برابر با 20 درصد است. همچنین علاوه بر نرخ رسوب‌گذاری، نرخ انتقال و اتصال حاصل از مدلسازی نیز آورده شده است. نتایج در این مورد نشان می‌دهند که برای رسوب ذرات آسفالتین، اتصال ذرات بسیار پراهمیت‌تر از انتقال ذرات است و به همین دلیل مدلسازی صحیح اتصال ذرات تاثیر زیادی در پیش‌بینی نرخ رسوب‌ ذرات آسفالتین دارد.
کلیدواژه‌ها

عنوان مقاله English

CFD modeling of Asphaltene deposition in turbulent flow inside heat exchanger pipe

نویسندگان English

Ashkan Torabi Farsani 1
Reza Maddahian 2
Amirhossein Nazari 1
Mohammad Mahdi Heyhat 3
1 Department of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran
3 Department of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran
چکیده English

In this research, the Asphaltene particles deposition is modeled using species transport equations. It is assumed that the deposition phenomenon consists of two steps: transport of Asphaltene particles toward the wall and attachment of them to the wall. Due to the small size of Asphaltene particles, their motion is simulated using species transport equation. Transport of Asphaltene particles is modeled by turbulent and Brownian diffusion and attachment mechanism is modeled employing first order chemical reaction. Effects of surface temperature and velocity is considered in the model. Finally the effects of velocity, surface temperature and Asphaltene concentration is investigated and compared with experimental data. The simulation results are agreed well with experimental data and the maximum error of is about 20 percentage. Also in addition of deposition rate, transport and attachment rate are investigated. The results indicate that Asphaltene attachment is more important than transport of Asphaltene, so accurate modelling of attachment has significant effect on prediction of Asphaltene deposition rate.

کلیدواژه‌ها English

Numerical simulation
Asphaltene deposition
attachment of particles
Species approach
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