Selma AKCAY, Ünal AKDAĞ, Oktay HACIHAFIZOĞU, Doğan DEMİRAL

Boru demeti üzerinden geçen Al2O3- su nanoakışkanın pulsatif akışının ısı transferine etkisi

Bu çalışmada, sabit duvar sıcaklığına sahip boru demetleri üzerinden geçen Al2O3-su nanoakışkanın laminer pulsatif akışının ısı transferine ve sürtünme faktörüne etkileri sayısal olarak incelenmiştir. Çalışmada, dairesel kesitli borular kademeli olarak yerleştirilmiş ve analizler iki boyutlu olarak gerçekleştirilmiştir. Kullanılan eşitlikler, sonlu hacimler metodu ile SIMPLE algoritması kullanılarak çözülmüştür. Sayısal incelemelerde, nanoakışkan tipi ve partikül hacim oranı sabit tutulmuş olup, analizler Reynolds sayısının sabit bir değeri için pulsatif parametrelerin değiştirilmesi ile elde edilmiştir. Bu parametrelerin ısı transferi karakteristiği ve sürtünme faktörü üzerindeki etkileri daimi akış şartları ile karşılaştırılmıştır. Boru demeti üzerinden pulsatif akışta anlık hız ve sıcaklık dağılımları elde edilmiştir. Sayısal sonuçlar, ısı transferindeki iyileşmenin pulsatif parametrelerden oldukça etkilendiğini göstermiştir. Pulsatif genlik ve frekans arttıkça ısı transferinin de arttığı, ancak bu artışın sürtünme faktöründe de bir miktar artışa sebep olduğu gözlemlenmiştir. Çalışma sonucunda boru demetleri üzerinden nanoakışkanların pulsatif akışı için en iyi termo-hidrolik performansı sağlayan parametreler belirlenmiştir. Sonuçlar boyutsuz parametrelerin bir fonksiyonu olarak verilmiştir.

Anahtar Kelimeler:

Boru demeti; Pulsatif akış; Nanoakışkanlar; Isı transferi; Sayısal çalışma

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