İç İçe Borulu Yay Tip Türbülatörlü Bir Isı Değiştiricisinin RNG k-ε Türbülans Modeli ile Sayısal Analizi

Öz

Bu çalışmada, eşmerkezli iç içe borulu bir ısı değiştiricisinin boyutlarının azaltılması ile ısı transferinin iyileştirilmesi ve sürtünme özelliklerinin belirlenmesi amacıyla yay tipi türbülatör kullanarak, RNG k-ε modeli ile sayısal analizler yapılmıştır. Çalışmalar Reynolds (Re) sayısının 3000 ila 18000 aralığında yapılmıştır. Sonlu Hacimler Metoduna dayalı ANSYS-fluent adlı bir Hesaplamalı Akışkanlar Dinamiği (HAD) kodu ile sayısal simülasyonlar yapılmıştır. Sayısal analizlerde, Model ➀ (RNG-Standard wall function), Model ➁ (RNG-Non-Equilibrium wall function) ve Model ➂ (RNG-Enhanced wall treatment) üç temel türbülans modelleri kullanılmıştır. Bu nedenle, deneysel ve sayısal analizlerle RNG k-ε modelinin üç temel türbülans modelleri arasında karşılaştırma yapılarak, en iyi sonucu Model ➀ türbülans modeli vermiştir.

Anahtar Kelimeler

• Türbülatör,HAD Analiz,RNG k-ε,Isı Değiştiricileri

Numerical Analisis by RNG k-ε Turbulent Model of a Concentric Tube Heat Exchanger with Coiled Wire Turbulator

Abstract

In this study, a concentric tube heat exchanger with coiled wire turbulators were analysised numerically by RNG k-ε Turbulent Model in order to be reduced heat exchanger sizes, increased heat transfer enhancement and to be obtained friction characteristics. The analyses were done in a range of Reynolds (Re) number from 3000 to 18000. The numerical simulations were done by using a CFD code namely ANSYS fluent, using finite volume method. Three main turbulence models of RNG k-ε were employed in the simulations such as Model ➀ (RNG-Standard wall function), Model ➁ (RNG-Non-Equilibrium wall function) and Model ➂ (RNG-Enhanced wall treatment). Therefore, the numerical analyses carried out to compare with the experimental results in order to determine the best fitting model using each three main turbulence models of RNG k-ε model, Model ➀ has given the best result.

Keywords

• Turbulator,CFD analysis,RNG k-ε,Heat Exchangers

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