MERKEZ DIŞI KATI İLETKEN BİR CİSİM İÇEREN DİKDÖRTGEN KAPALI BİR ORTAMDA SU BAZLI CuO NANOAKIŞKANLAR İÇİN KALDIRMA KUVVETİ ETKİLİ ISI TRANSFERİNİN NÜMERİK İNCELENMESİ

Bu çalışmada, katı bir silindir içeren dikdörtgensel kapalı bir ortamda su bazlı CuO nanoakışkanlar için kaldırma kuvveti etkili ısı transferi farklı yükseklik genişlik oranı, katı silindirin yeri ve çapı, nanoparçacık hacim oranı ve Rayleigh sayısı değerleri için nümerik olarak incelenmiştir. Kapalı ortamın alt ve üst duvarları adyabatik iken, yan duvarları izotermaldir. Silindirin ısı iletim katsayısının baz akışkanınkine eşit olduğu varsayılmıştır. Yönetici denklemler Comsol Multiphysics sonlu eleman modelleme ve simülasyon yazılımı kullanılarak nümerik olarak çözülmüştür. Sonuçlar, ısı transferinin Rayleigh sayısı ve nanoparçacık hacim oranının artışı ve katı silindir çapının düşüşü ile önemli ölçüde arttığını göstermiştir. Sonuçlar aynı zamanda Rayleigh sayısının düşük değerleri için ısı transferinin yükseklik genişlik oranının artışı ile arttığını göstermiştir. Sonuçlar ayrıca ısı transferinin en yüksek değerlerini Rayleigh sayısının yüksek değerleri ve karesel kapalı ortam durumu için aldığını göstermiştir.

NUMERICAL INVESTIGATION OF BUOYANCY DRIVEN HEAT TRANSFER OF WATER-BASED CuO NANOFLUIDS IN A RECTANGULAR ENCLOSURE WITH AN OFFCENTER SOLID CONDUCTING BODY

Abstract: In this study, buoyancy driven heat transfer of water-based CuO nanofluid in a rectangular enclosure with asolid cylinder was investigated numerically for different values of aspect ratio, location and diameter of solid cylinder,solid volume fraction and Rayleigh number. While bottom and upper walls of enclosure are adiabatic, sidewalls areisothermal. Thermal conductivity of solid cylinder was assumed to be equal to that of the base fluid. Governingequations were solved numerically by Comsol Multiphysics finite element modeling and simulation software. Resultsshow that heat transfer rate increases considerably with an increase in the Rayleigh number and solid volume fractionand with a decrease in the solid cylinder diameter. Results also show that heat transfer rate shows an increase with anincrease of aspect ratio for low values of Rayleigh number. Finally, results show that heat transfer rate gets its highestvalue for square enclosure case for high values of Rayleigh number.

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