نویسنده
دانشکده مهندسی مکانیک، دانشگاه علم و صنعت ایران، تهران
چکیده
در این پژوهش، جریان جابه‌جایی آشفته نانوسیال آب و اکسید مس در یک کانال قائم به‌صورت عددی مورد بررسی و تحلیل قرار می‌گیرد. جهت مدل‌سازی جریان فاز سیال به‌صورت پیوسته درنظر گرفته می‌شود، در حالی که نانوذرات به‌صورت فاز گسسته در سیال پایه پخش شده‌اند. نحوه پخش نانوذرات اکسید مس در سیال پایه در شرایط جریانی مختلف مطالعه می‌شود تا مکانیزم‌های مؤثر بر توزیع نانوذرات در مقطع کانال مشخص شود. نتایج مبین این نکته است که در شرایط جریان جابه‌جایی آشفته و در ناحیه کاملاً توسعه یافته اثر پدیده ترموفورسیس بر حرکت براونی نانوذرات غلبه کرده و از این‌رو تجمع ذرات در نواحی مرکزی کانال بیشتر است. اما در ناحیه ورودی که لایه مرزی به‌طور کامل شکل نگرفته است، توزیع نانوذرات یکنواخت‌تر است. همچنین افزایش کسر حجمی نانوذرات به افزایش نوسانات سرعت آشفتگی در نواحی نزدیک به دیواره کمک کرده و این اثر متقابل موجب بهبود بیشتر انتقال حرارت در جریان آشفته نسبت به جریان آرام می‌شود.
کلیدواژه‌ها
عنوان مقاله [English]
Analysis of Particle Dispersion in Turbulent Mixed Convection of CuO-water Nanofluid
نویسنده [English]
- F. Bazdidi Tehrani
چکیده [English]
In the present paper, turbulent convection of CuO-Water Nanofluid in a vertical channel is investigated numerically. In order to simulate the flow, the fluid is considered as a continuous phase while the discrete nanoparticles are dispersed through it. The dispersion of CuO nanoparticles in different flow conditions are studied in order to find the effective mechanisms of particles dispersion in the channel. The results show that in the fully developed turbulent convection flow, thermophoresis is more dominant than Brownian motion of nanoparticles and therefore the nanoparticles aggregation are more in the central areas of the channel. While in entrance region, where the boundary layer is not fully formed, the particles dispersion are more uniform. Also, an increase in the nanoparticles concentration will increase the turbulent velocity fluctuations in regions near the wall and this two-sided effect will cause improvement in turbulent flow thermal transmitance than the laminar flow.
کلیدواژه‌ها [English]
- Nanofluid
- Turbulent convection
- Dispersion of particles
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