Title of article :
Experimental Investigation of Mixed Convection Heat Transfer in Vertical Tubes by Nanofluid: Effects of Reynolds Number and Fluid Temperature
Author/Authors :
Rostamzadeh, A Department of Mechanical Engineering - Engineering School - Shiraz University, Shiraz, Iran , Jafarpur, K Department of Mechanical Engineering - Engineering School - Shiraz University, Shiraz, Iran , Goshtasbirad, E Department of Mechanical Engineering - Engineering School - Shiraz University, Shiraz, Iran , Doroodmand, M. M Department of Chemistry - Faculty of Science - Shiraz University, Shiraz, Iran
Abstract :
An experimental investigation was carried out to study mixed convection heat transfer from Al2O3-
water nanofluid inside a vertical, W-shaped, copper-tube with uniform wall temperature. The tests
covered different ranges of some involved parameters including Reynolds number, temperature and
particles volume fraction. The results showed that the rate of heat transfer coefficient improved with
Reynolds number for average wall temperatures of 50 and 60ºC. Additionally, the heat transfer
coefficient increased slightly with an increase of the Reynolds number. Interestingly, the pressure drop
of nanofluid was very close to that of base fluid. Besides, a new correlation was proposed to calculate
the Nusselt number in W-shaped tubes.
Farsi abstract :
در اين مطالعه انتقال حرارت جابجايي نانو سيال آلومينا، درون يك لوله مسي عمودي و W شكل با شرط مرزي دماي ديوار ثابت مورد مطالعه قرار گرفته است . آزمايشات انجام شده محدوده اي از پارامترها نظير عدد رينولدز، دما و غلظت نانو ذرات را در بر مي گيرد. نتايج نشان دهنده بهبود نرخ ضريب انتقال حرارت با عدد رينولدز در دماي متوسط ديواره 50 و 60 درجه سانتي گراد است. علاوه بر آن نرخ انتقال حرارت با افزايش عدد رينولدز اندكي افزايش مي يابد. همچنين افت فشار نانو سيال بسيار نزديك به سيال پايه است و در نهايت رابطه اي براي محاسبه عدد ناسلت درون لوله W شكل پيشنهاد شده است.
Keywords :
nanofluid , mixed convection , alumina nanoparticles , heat transfer
Journal title :
Astroparticle Physics
