Heat Transfer Enhancement in Turbulent Flows by Blocked Surfaces

Abstract

In this study, the heat transfer analyses over flat and blocked surfaces were carried out in turbulent flow under the influence of the block height. A constant-temperature hot wire anemometer was used to the velocity and turbulent intensity measurements, while temperature values were measured by copper-constantan thermocouples. The average Stanton numbers for block heights of 15 and 25 mm were higher than those of flat surface by %38 and %84, respectively. The results showed that the presence of the blocks increased the heat transfer and the enhancement rose with block heights

Keywords

• Blocked surface, Turbulent flow, Heat transfer enhancement

Türbülanslı Akışta Isı Transferinin Bloklu Yüzeyler ile Arttırılması

Abstract

Bu çalışmada, düz ve bloklu yüzeyler üzerinde türbülanslı akış için ısı transferi analizi blok yüksekliğine bağlı olarak yapılmıştır. Hız ve türbülans yoğunlukları ölçümlerinde sabit sıcaklıklı bir kızgın tel anemometresi kullanılırken, sıcaklık değerleri termal çiftler ile ölçülmüştür. 15 ve 25 mm blok yüksekliklerine sahip bloklu yüzey ortalama Stanton sayılarının, düz yüzey değerlerinden sırasıyla %38 ve %84 daha fazla olduğu tespit edilmiştir. Bu sonuçlar, blokların varlığının ısı transferini önemli derecede arttırdığını ve ısı transferinin blok yüksekliği ile arttığını göstermektedir

Keywords

• Bloklu yüzey, Türbülanslı akış, Isı transferi artırımı

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17. Makale 19.06.2012 tarihinde alınmış, 19.11.2012 tarihinde düzeltilmiş, 21.11.2012 tarihinde kabul edilmiştir.