Halisel Türbülatörün Isı Geçmişine Etkisinin Sayısal İncelenmesi

Year 2011, Volume: 24 Issue: 2, 71 - 84, 30.12.2011

Nihal Uğurlubilek , İ. Yalçın Uralcan

Abstract

Bu çalışamada, 18 mm çaplı bakır bir borunun içine sıkı geçme
olarak konulan helisel bir türbülatörün ısı geçişine etkisi saysal olarak
incelenmiştir. Çalışma akışkanı su kabul edilmiştir (Pr=2,45). Reynolds sayısı 1000-20.000 aralığında alınmıştır. Dış ortamda kaynama olduğu kabul edilmiştir.
Boru boyu ve et kalınlığı sırasıyla 250 ve 1 mm’ dir. Üç farklı sarım sayısı (5, 10 ve 20) kabul edilmiştir. Korunum denklemleri Simple algoritmasõ ve türbülanslı akış modeli olarak Realizable k3 modeli kullanılarak çözülmüştür. Üç farklı
geometri için sayısal olarak bulunan Nusselt değerleri, Reynolds Sayısına bağlı olarak kaynaklardaki mevcut bağlantılardan elde edilen değerlerle
karşılaştırılmıştır.  Sonuç olarak;
helisel türbülatörlü boruların laminer akışta düz boruya göre ısı geçişini
arttırdığı türbülanslı akışta ise termodinamik açıdan verimli olmadığı görülmüştür.

Keywords

ısı geçişi, sayısal, helisel türbülatör, taşınım, tek fazlı akış

Numerıcal Investıgatıon Of The Effect Of Helıcal Turbulator On The Heat Transfer

Abstract

In this study, heat transfer in the case of a helical turbulator inserted in a copper tube with 18 mm hydraulic diameter is investigated numerically. The water is taken as the working fluid (Pr=2,45). Reynolds number is chosen 1000-20.000. It is considered the boiling condition at the outher surface of the pipe. The pipe length and wall thickness are considered 250 and 1 mm, respectively. Three different number of turns (5, 10 and 20) were accepted. The governing equations are solved using Simple algoritm and Realizable kmodel for turbulent regime. The Nusselt number calculated by numerical study and  existing correlations in literature are compared each other depending on Reynolds number for the three different geometry. In conclusion; it has been seen that, in the case of laminar flow, the pipe with helical  turbulator  increases the heat transfer more than the straight pipe, whereas in the case of turbulent flow,  it isn’t  productive in terms of thermodynamics.

Keywords

Heat Transfer, Numerical, Helical Turbulator, Convection, Single Phase. .

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