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

Year 2020, Volume: 8 Issue: 1, 64 - 78, 23.03.2020

Haci Mehmet Şahin , Ali Riza Dal , Medine Özkaya

https://doi.org/10.29109/gujsc.625585

Cited By: 5

Abstract

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.

Keywords

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

References

• Yakut, K., Şahin, B. Flow-induced vibration analysis of conical rings used for heat transfer enhancement in heat exchangers. Applied Energy,78 (2004) 273–288.
• Sahin, H.M., Baysal, E. Dal, A.R. and Sahin, N. Investigation of heat transfer enhancement in a new type heat exchanger using solar parabolic trough systems. International Journal of Hydrogen Energy, 40: 44 (2015) 15254-15266.
• Baysal, E. (2009). Eşmerkezli Borulu Isı Değiştiricilerinde Helisel Türbülatörlerin Etkilerinin Deneysel ve Sayısal Olarak İncelenmesi, Fen Bilimleri Enstitüsü, Doktora Tezi, Gazi Üniversitesi, Ankara.
• ANSYS FLUENT 12.0. Theory Guide; 4.12.4, 2010.
• Sahin, H.M., Baysal, E., Dal, A.R. Experimental and numerical investigation of thermal characteristics of a novel concentric type tube heat exchanger with turbulators. International Journal of Energy Research, 37 (2013) 1088–1102.
• Saraç, B. A., Bali, T. An experimental study on heat transfer and pressure drop characteristics of decaying swirl flow through a circular pipe with a vortex generator. Experimental Thermal and Fluid Science 32 (2007) 158–165.
• Akpınar, E.K., Biçer, Y., Yıldız, C., Pehlivan, D. Heat transfer enhancements in a concentric double pipe exchanger equipped with swirl elements. Int. Comm. Heat Mass Transfer, 31: 6 (2004) 857-868.
• Promvonge, P., Eiamsa-ard, S. Heat transfer enhancement in a tube with combined conical-nozzle inserts and swirl generator. Energy Conversion and Management, 47 (2006) 2867–2882.
• Eiamsa-ard, S., Promvonge, P. Experimental investigation of heat transfer and friction characteristics in a circular tube fitted with V-nozzle turbulators. International Communications Heat and Mass Transfer, 33 (2006) 591-600.
• Neshumayev, D., Ots, A., Laid, J., Tiikma, T. Experimental investigation of various turbulator inserts in gas-heated channels. Experimental Thermal and Fluid Science, 28 (2004) 877–886.
• Shokouhmand, H., Salimpour, M.R., Akhavan-Behabadi, M.A. Experimental investigation of shell and coiled tube heat exchangers using wilson plots. International Communications in Heat and Mass Transfer, 35 (2008) 84–92.
• Naphon, P. Effect of coil-wire insert on heat transfer enhancement and pressure drop of the horizontal concentric tubes. International Communications in Heat and Mass Transfer, 33 (2006) 753–763.
• Kongkaitpaiboon, V., Nanan, K., Eiamsa-ard, S. Experimental investigation of convective heat transfer and pressure loss in a round tube fitted with circular-ring turbulators. International Communications in Heat and Mass Transfer, 37: 5 (2010) 568-574.
• Aköz, M.S., Soydan, N.G., Şimşek, O. Kritik Üstü Açık Kanal Akımının Detached Eddy ve Large Eddy Simülasyon ile Sayısal Modellenmesi. Gazi Üniversitesi Fen Bilimleri Dergisi Part C: Tasarım ve Teknoloji, 4: 4 (2016) 213 – 224.
• Ekici, Ö., Özcan, Z. Akış Problemleri İçin Lattice Boltzmann Yöntemi ve Uygulamaları, Gazi Üniversitesi Fen Bilimleri Dergisi Part C: Tasarım ve Teknoloji, 4: 3 (2016) 115 – 126.
• Zhang, G., Tian, M. Simulation and analysis of flow pattern in cross-corrugated plate heat exchangers. Journal of Hydrodynamics, Ser. B., 18: 5 (2006) 547-551.
• Gimbun J., Chuah T. G., Fakhru’l-Razi A., Choong, T. S. Y. The influence of temperature and inlet velocity on cyclone pressure drop: a CFD study. Chemical Engineering and Processing, 44 (2005) 7-12.
• Eimsa-ard, S., Promvonge, P. Numerical study on heat transfer of turbulent channel flow over periodic grooves. Int. Communications in Heat and Mass Transfer, 35 (2008) 844-852.
• Yakhot, V., Orszag, S. A. Renormalizatıon Group Analysis of Turbulence. I. Basic Theory, Journal of Scientific Computing, 1: 1 (1986) 3-51.
• Yakhot V., Orszag, S. A., Thangam, S., Gatski, T. B., Speziale, C. G. Development of turbulence models for shear flows by a double expansion technique. Physics of Fluids A, 4 (1992) 1510-1520.
• Petukhov, B.S., Irvine, T. F., Hartnett, J. P. (1970) Advances in heat transfer. Vol. 6, Academic Press, New York.
• Shih, T.H., Liou, W.W., Shabbir, A., Yang, Z., Zhu, J. A new k-epsilon eddy-viscosity model for high Reynolds number turbulent flows. Model Development and Validation, Computers Fluids, 24: 3 (1995) 227-238.
• Yiğit, M. (2016). İç İçe Borulu Yay Tipi Türbülatörlü Bir Isi Değiştiricisinde Türbülans Modelinin Isı Transferine Etkisinin İncelenmesi, Fen Bil. Enst., Yüksek Lisans Tezi, Gazi Üniversitesi, Ankara.
• Kline, S.J., McClintock, F.A. Describing uncertainties in single sample experiment. Mech. Eng. 75 (1953) 385–387.