Numerical Investigation on Heat Enhancement Method with Using Circular Dimpled Tube

Year 2019, Volume: 3 Issue: 1, 19 - 31, 29.03.2019

Toygun Dağdevir , Orhan Keklikcioglu , Veysel Ozceyhan , Sibel Gunes

https://doi.org/10.31200/makuubd.481202

Cited By: 1

Abstract

In this
study, the effect of dimpled tube which is heated with constant heat flux on
heat transfer enhancement is numerically investigated Using physically enhanced
tube is one of the passive heat transfer enhancement methods. The reason of
using dimpled tube is increase turbulence through the tube and destruct the
thermal boundary layer. The numerical study is validated with an experimental
study and configurations of cases are expanded with chancing pitch length. The
considered cases are conducted in Reynolds number range of 3000 to 8000. Used
fluid through the flow and its material copper are selected as water and
copper, respectively. The k- ε RNG turbulence model is used to simulate
turbulent flow adjacent the inner wall surface. The analyses are determined
with Nusselt number (Nu), friction factor (f) and performance evaluation
criteria (PEC).  The highest Nusselt
number and the minimum friction factor is obtained when the Reynolds number of
8000, as 135.54 and 0.0599, respectively, for pitch length of 10 mm and 50 mm.
The highest THP value is observed as 2.01 by the case of pitch length of 10 mm
and Reynolds number of 3000.

Keywords

Dimpled tube, Numerical study, Heat transfer, Performance evaluation criteria

Dairesel Oyuntu ile Isı Transferi İyileştirilmesi Üzerine Sayısal Araştırma

Abstract

Bu çalışmada sabit ısı akısı ile ısıtılmış bir boruya oyuntu yerleştirilmesinin ısı transferi
iyileştirilmesi üzerindeki etkisi sayısal olarak araştırılmıştır. Fiziksel olarak boru üzerinde
yapılan iyileştirme ısı transferi iyileştirilmesinin pasif metotlarından birisidir.
Oyuntulaştırılmış boru kullanımının sebebi akış boyunca türbülansı arttırmak ve termal sınır
tabakayı parçalamaktır. Sayısal çalışma, deneysel başka bir çalışma ile doğrulanmış ve
incelenen değişen hatve uzunlukları genişletilmiştir. İncelenen analizler Reynolds sayısının
3000’den 8000’ e kadar gerçekleştirilmiştir. Akış boyunca kullanılan akışkan ve boru
malzemesi sırasıyla su ve bakır olarak seçilmiştir. İç duvar etrafındaki türbülanslı akışın
simülasyonu için k-ε RNG türbülans modeli kullanılmıştır. Analizlerin sonuçları Nusselt
sayısı (Nu), sürtünme katsayısı (f) ve performans değerlendirme kriteri (PEC) ile
değerlendirilmiştir. En yüksek Nu ve en düşük f Re sayısı 8000 iken, sırasıyla 130.54 ve
0.0453 olarak, hatve uzunluğunun sırasıyla 10 mm ve 50 mm olduğu durumlarda elde
edilmiştir.

Keywords

Oyuntulaştırılmış boru, Sayısal çalışma, Isı transferi, performans değerlendirme kriteri

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