بررسی انتقال حرارت جابه‌جایی آزاد محفظة پرشده از نانوسیال با یک مانع با طول متغیر و تحت میدان مغناطیسی

نوع مقاله: مقاله پژوهشی

نویسندگان

1 عضو هیات علمی / دانشکدة مهندسی مکانیک، دانشگاه ولی عصر (عج)، رفسنجان

2 کارشناسی ارشد مهندسی مکانیک / دانشگاه آزاد اسلامی واحد شهرکرد، شهرکرد

چکیده

کاهش وزن، ابعاد و مصرف انرژی از جمله مسائل حائز اهمیت در صنایع هوافضا (فضاپیماها و ایستگاه فضایی) است. همین موارد سبب نیاز به یک سیستم خنک‌کننده با قابلیت بالا و ابعاد کوچکتر می‌شود. نانوسیالات می‌توانند در سیستم‌های سردکننده نقشی حیاتی ایفا کنند. در این مقاله به بررسی عددی جریان آرام، لایه­ای با جابه‌جایی طبیعی نانوسیال، در یک محفظة مربعی تحت زوایای مختلف نسبت به افق با مانعی در وسط آن پرداخته شده است. در وسط محفظه، صفحه­ای عمودی با ضخامت ناچیز قرار دارد. معادلات حاکم به روش تفاضل محدود، مبتنی بر حجم کنترل جبری شده و به‌کمک الگوریتم سیمپل به‌صورت هم­زمان حل شده­اند. بر اساس نتایج حاصل از حل عددی، تأثیر پارامترهایی چون چرخش محفظه، عدد ریلی، نسبت حجمی ‌نانوذرات و عدد هارتمن بر میدان جریان و انتقال حرارت بررسی شده ­است. نتایج نشان می‌دهند که در چرخش محفظه، ماکزیمم انتقال حرارت وقتی صورت می­پذیرد که صفحة گرم با افق دارای زاویة 45 درجه باشد. صفحة میانی و افزایش عدد هارتمن موجب کاهش انتقال حرارت می­شوند، حال آنکه افزایش عدد ریلی موجب افزایش انتقال حرارت می­شود. افزایش نسبت حجمی ‌نانوذرات بسته به عدد ریلی ممکن است عملکرد حرارتی را تقویت یا تضعیف نماید.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

The investigation of buoyancy-driven heat transfer in a square cavity with multiple mounted variable length heaters under magnetic field

نویسندگان [English]

  • Alireza Arab Solghar 1
  • Mohammad Shafiey Dehaj 1
  • Mahdi Davoodian 2
1 Assistant Professor / Department of Mechanical Engineering, Vali-e-Asr University, Rafsanjan
2 Master of Science / Department of Mechanical Engineering, Islamic Azad University, Sahre Kord
چکیده [English]

Weight loss, dimensions, and energy consumption are important issues in the aerospace industry (spacecraft and space station), which requires a high capacity cooling system and smaller dimensions. Nanofluids can play an important role in cooling systems. In this paper, natural convection of water-alumina nanofluid in a square cavity with a thin partition mounted at the middle of the cavity is studied. The cavity has different orientation angles with respect to the horizon. For the horizontal cavity, the top and bottom walls are adiabatic and the left and the right walls are considered to be hot and cold, respectively. At the center of cavity, a vertical baffle with negligible thickness is mounted. The nanofluid inside the cavity is under a magnetic field. Governing equations were discretized through control volume approach and were solved simultaneously applying SIMPLER algorithm. Based on obtained results from numerical method, the influence of pertinent parameters such as the orientation angle of the cavity, Rayleigh number, the volume fraction of nanoparticles and Hartman number on the flow field and heat transfer are investigated. The results show that maximum heat transfer occurs when the angle of hot wall with respect to the horizon is 45. Also, the existence of the baffle and increase of Hartman number reduce the heat transfer while the increase of Rayleigh number enhances the transfer of heat. Depending on Rayleigh number, the increase of nanoparticle volume fraction may increase or decrease the thermal performance.

کلیدواژه‌ها [English]

  • free convection
  • cavity
  • nanofluid
  • heat transfer rate

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