Numerical Investigation of Nanofluid Applications in Military System

Öz

Abstract

 

In this study, enhancement of heat transfer from high heat flux surface was investigated numerically by using nanofluids and impinging jet technique to solve the problem of increasing heat loads which is caused by developing technologies of military sistems. Effect of different Reynolds number (Re=2000, 4000, 6000, 8000) and different type of nanofluids (Cu-H2O, CuO-H2O, TiO2-H2O, Al2O3-H2O) on heat transfer are the parameters of this study. Low Re k-ε model was used. It was obtained that increasing Re number causes an increase on local Nusselt number. Increasing Reynolds number from 4000 to 8000 causes an increase of 47.2% on average Nusselt number for Cu-H2O nanofluids (particle diameter of 20 nm and volume ratio of 4%). It was determined that using Cu-H2O nanofluid causes an increase of 2.6%, 5.5%, 6.1% and 9.6% on average Nusselt number with respect to CuO-H2O, TiO2-H2O, Al2O3-H2O and pure water. It was seen that the low Reynolds number k-ε turbulence model well represents the temperature distribution and flow properties at this study.

Anahtar Kelimeler

• Biosystems,impinging jets,Heat Transfer,Nanofluids

Askerî Sistemlerde Nanoakışkan Uygulamalarının Sayısal İncelemesi

Öz

Öz

 

Bu çalışmada; askerî sistemlerin gelişen teknolojiye bağlı olarak artan ısıl yük problemini çözmek maksadıyla, nanoakışkanların çarpan akışkan jet tekniği ile kullanılarak, yüksek ısı akılı bir yüzeyden olan ısı transferinin iyileştirilmesi sayısal olarak incelenmiştir. Farklı Reynolds sayıları (Re=2000, 4000, 6000, 8000) ve farklı tipte hazırlanan nanoakışkanların (Cu-H₂O, CuO-H₂O, TiO₂-H₂O, Al₂O₃-H₂O) ısı transferine etkisi bu çalışmada kullanılan parametrelerdir. Çalışmada düşük Reynolds sayılı k-ε türbülans modeli kullanılmıştır. Sonuç olarak; Re sayısı arttıkça yerel Nu sayısının arttığı görülmüştür. Cu-H₂O nanoakışkanı için (20 nm parçacık çapında, % 4 hacimsel oranda) Re sayısı 4000-8000 aralığında artırıldığında Nu_ort sayısında %47,2’lik bir artış elde edilebildiği tespit edilmiştir. Cu-H₂O nanoakışkanı kullanılması durumunda, ortalama Nusselt sayısında sırasıyla CuO-H₂O, TiO₂-H₂O, Al₂O₃-H₂O ve saf suya göre %2,6, %5,5, %6,1, %9,6 iyileşme olduğu görülmüştür. Sayısal modelde kullanılan düşük Reynolds sayılı k-ε türbülans modelinin sıcaklık dağılımını ve akış özelliklerini oldukça iyi bir şekilde temsil edebildiği görülmüştür.

Anahtar Kelimeler

• Biyolojik sistemler,Çarpan Akışkan Jet,Isı Transferi,Nanoakışkanlar

Kaynakça

1. Kaynakça
2. Makaleler
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4. Yayınlanmış Bildiri Metinleri
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