شبیه‌سازی عددی عملکرد سایکلون گاز - جامد در دماهای بالا

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی مکانیک و هوا فضا، دانشگاه صنعتی مالک اشتر اصفهان، اصفهان، ایران

چکیده

بر خلاف هندسه‌ ساده‌ی سایکلون‌ها، جریان درون آن‌ها بسیار پیچیده است. یکی از عواملی که این پیچیدگی را چند برابر می‌کند، تغییر درافت فشار جریان و راندمان جمع‌آوری ذرات جامد  بر اثر تغییر دمای کاری آن است. دمای سیال یکی از پارامترهای تاثیرگذار بر رفتار جریان است. تغییر دمای سیال موجب تغییر خواص ترموفیزیکی و درنتیجه تغییر در الگوهای جریانی آن می‌شود. در این مقاله، اثر دمای سیال ورودی بر دو مشخصه‌ عملکردی مهم سایکلون استیرماند راندمان بالا، افت فشار و راندمان جداسازی، با استفاده از اصول دینامیک سیالات محاسباتی موردمطالعه قرار گرفته است. جریان دوفازی درون سایکلون با رویکرد اویلری – لاگرانژی مدل‌سازی شد. شبیه‌سازی در محدوده‌ی دمایی 700-293 کلوین و در چهار سرعت ورودی مختلف با استفاده از روش حجم محدود به کمک مدل تلاطمی تنش رینولدز در شرایط نا پایا انجام شد. بررسی نتایج نشان می‌دهد که با افزایش دما، میزان چرخش ذرات و جریان در بدنه‌ی سایکلون کاهش‌یافته و درنتیجه، راندمان و افت فشار کاهش می یابند. به ازای هر 100 کلوین افزایش دما، بین 14% تا 16% کاهش افت فشار در دبی‌های مختلف مشاهده می‌شود. همچنین راندمان جمع‌آوری ذرات هم بین بیشینه و کمینه‌ی دما، حداکثر 64/4% کاهش می‌یابد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Numerical Simulation of Gas – Solid Cyclone Separators Operating at High Temperatures

نویسندگان [English]

  • M. Siadaty
  • S. Kheradmand
Mechanical and Aerospace Engineering Department, Malek - Ashtar University of Technology, Shahinshahr, Isfahan, Iran
چکیده [English]

Although cyclones have simple geometries their flow is really complicated. Inlet fluid temperature is one of the factors that increases its complexity. Variation of the thermo-physical properties of the working fluid with temperature causes cyclones to have different pressure drop and particle separation efficiency. In this paper, the effect of fluid and particles temperature on two main performance parameters (pressure drop and separation efficiency) of low-mass-loading Stairmand high efficiency cyclone are numerically investigated. Eulerian-Lagrangian approach is used to model twophase flow. Simulation is performed at a temperature range of 293-700 K and four inlet velocities. Also,
the turbulent equations are solved with unsteady Reynolds stress method. Results show that increasing in dynamic viscosity due to increase in fluid temperature, causes increment in shear stress in cyclone body. Therefore, separation efficiency and pressure drop are decreased. If the inlet flow temperature increases by 100 K, pressure drop decreases between 14% and 16% at different inlet velocities. Also, separation efficiency is decreased by 4.64% between the minimum and maximum of inlet temperatures.

کلیدواژه‌ها [English]

  • High efficiency Stairmand cyclone
  • Computational fluids dynamics
  • Temperature
  • Pressure drop
  • EFFICIENCY

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نشریه مهندسی مکانیک امیرکبیر
دوره 49، شماره 3
آبان 1396
صفحه 495-506

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