جابجایی ترکیبی نانوسیال آب- اکسید آلومینیوم در یک محفظه مربعی باز حاوی یک قطعه جامد گرمازا

نویسندگان

دانشگاه شهرکرد

چکیده

در این تحقیق انتقال حرارت جابجایی ترکیبی نانو سیال آب- اکسید آلومینیوم در یک محفظه مربعی حاوی یک جسم جامد گرمازا به روش عددی بررسی شده است. نانو سیال با دما و سرعت یکنواخت از گوشه ی پایین و سمت چپ محفظه وارد آن می شود و به صورت توسعه یافته از گوشه ی بالا و سمت راست محفظه خارج می شود. جسم جامد قرار گرفته در مرکز محفظه، به صورت یکنواخت انرژی تولید می کند. تمام دیواره های محفظه از نظر حرارتی عایق هستند. معادلات دیفرانسیل حاکم با استفاده از روش حجم محدود گسسته شده‌اند و با استفاده از الگوریتم سیمپل حل شده اند. در این تحقیق اثر پارامترهای مختلف از قبیل کسر حجمی نانوذرات، عدد ریچاردسون، عدد رینولدز، نسبت منظری و ضریب هدایت حرارتی منبع گرمازا بر روی میدان جریان و نرخ انتقال حرارت بررسی شده است. نتایج نشان می دهد که با افزایش اعداد رینولدز و ریچاردسون عدد نوسلت و نرخ انتقال حرارت افزایش می‌یابد. تغییر اندازه‌ی ضلع منبع حرارتی باعث تغییر میدان‌های جریان و میدان دما می‌شود. افزایش ضریب هدایت حرارتی منبع حرارتی باعث افزایش میزان انتقال حرارت از منبع گرمازا به نانوسیال مجاور آن می‌شود. همچنین با افزایش کسر حجمی نانوذرات ، میزان انتقال حرارت زیاد می شود.

کلیدواژه‌ها


عنوان مقاله [English]

Mixed Convection of a Water-Al2O3 Nanofluid in an Open Square Cavity, Containing a Solid Body Heat Source

چکیده [English]

In this study, mixed convection of a water-Al2O3  nanofluid was numerically investigated in an open square cavity. All cavity walls were insulated and a solid body heat source was placed at the center of the cavity. The nanofluid enters the cavity with uniform velocity and temperature and leaves it as a fully developed flow. The governing equations were discretized using finite volume method and using Patankar’s SIMPLE algorithm. The effects of relevant parameters, such as Reynolds and Richardson numbers, length ratio (The ratio of the heat source length to the length of the cavity), the source thermal conductivity, and solid volume fraction of the nanoparticles were examined, both from flow field and the heat transfer rate considerations. The results show that the average Nusselt number increases with increase in Reynolds and Richardson numbers. A change in length ratio changes the flow and temperature fields. In addition, Increase of heat source thermal conductivity increases the average Nusselt number. The results also show that thermal performance of cavity is enhanced by increasing solid volume fraction of the nanoparticles.  

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