Konik sarımlı yay elemanlarının kaynamalı iki fazlı akış rejimlerine etkisi

Öz

Bu çalışmada, yatay borularda gerçekleşen iki fazlı kararlı akış koşullarında, yüzey artırıcı eleman olarak kullanılan konik sarımlı yay (çapı azalan ve artan yönde) dizisinin ısı transferi ve akış kararsızlıklarına etkisi deneysel olarak incelenmiştir. Deneyler, sabit giriş sıcaklığı (15 °C), sabit ısıl güç (22 kW) ve sabit çıkış kısıtlaması altında iki farklı boru tipinde (boş boru ve konik yay dizili boru) gerçekleştirilmiştir. Kütlesel debi 72 g/s’den başlayarak 17 g/s’ye kadar kademeli olarak azaltılmış ve her kademede sistemin kararlı duruma ulaşması beklenerek ölçümler alınmıştır. Deneysel sonuçlar, yüzey artırıcı eleman kullanılan boruda (Boru-2) basınç düşümünün düz boruya (Boru-1) kıyasla daha yüksek olduğunu, ancak akışın daha homojen ve dengeli bir şekilde gerçekleştiğini göstermektedir. Ayrıca, cidar sıcaklıkları daha düşük seviyelerde seyretmiş ve üst-alt cidar sıcaklıkları arasındaki fark azalmıştır. Bu durum, konik yay elemanının oluşturduğu türbülans sayesinde sıvı ve buhar fazlarının daha iyi karışmasına bağlanmıştır. Burn-out olayının daha düşük sıcaklıklarda gerçekleştiği, böylece boru cidarının aşırı ısınmaya karşı daha iyi korunduğu gözlemlenmiştir. Elde edilen veriler, bu tür yüzey artırıcı elemanların iki fazlı ısı transfer sistemlerinde ısıl performansı artırırken aynı zamanda sistem kararlılığını da olumlu yönde etkilediğini ortaya koymuştur. Çalışma, özellikle kaynamalı akış içeren mühendislik sistemlerinde, güvenli ve verimli tasarım açısından önemli katkılar sunmaktadır.

Anahtar Kelimeler

• İki fazlı akış
• Kaynamalı ısı transferi
• Akış kararsızlığı
• Isı transferi iyileştirmesi
• Konik yay

Effect of conical helical spring elements on boiling two-phase flow regimes

Abstract

In this study, the effects of a conical helical spring insert (with decreasing and increasing diameter along the flow direction), used as a surface enhancement element, on heat transfer and flow instability under steady-state two-phase flow conditions in horizontal tubes were experimentally investigated. The experiments were conducted at a constant inlet temperature (15 °C), a constant heat input (22 kW), and a fixed outlet restriction, using two different tube configurations: a smooth tube and a tube equipped with a conical helical spring insert. The mass flow rate was gradually decreased from 72 g/s to 17 g/s, and measurements were taken after the system reached steady-state conditions at each stage. Experimental results showed that the pressure drop in the tube with the surface enhancement element (Tube-2) was higher compared to the smooth tube (Tube-1), but the flow occurred more homogeneously and uniformly. Moreover, the wall temperatures were observed to be lower, and the temperature difference between the upper and lower tube walls decreased. This behavior is attributed to improved mixing of the liquid and vapor phases due to turbulence generated by the conical helical spring. The burn-out phenomenon occurred at lower wall temperatures, indicating better protection of the tube wall against overheating. The results indicate that these surface enhancement elements not only improve thermal performance in two-phase heat transfer systems but also enhance flow stability. This study provides important insights for achieving safe and efficient designs, especially in engineering systems involving boiling flow.

Keywords

• Two-phase flow
• Boiling heat transfer
• Flow instability
• Heat transfer enhancement
• Conical spring

References

1. [1] N. Iwata and F. Bozzoli, “Investigation of operational limit of a pulsating heat pipe by estimating local heat transfer,” Exp. Comput. Multiph. Flow, vol. 6, no. 3, pp. 265–276, 2024, doi: 10.1007/s42757-023-0179-5.
2. [2] C. Wang et al., “Dynamic analysis for ultra-supercritical boiler water wall considering uneven heat flux distribution and combustion instability,” Int. J. Heat Mass Transf., vol. 236, no. P1, p. 126269, 2025, doi: 10.1016/j.ijheatmasstransfer.2024.126269.
3. [3] T. Xue and S. Zhang, “Investigation on heat transfer characteristics of falling liquid film by planar laser-induced fluorescence,” Int. J. Heat Mass Transf., vol. 126, pp. 715–724, 2018, doi: 10.1016/j.ijheatmasstransfer.2018.05.039.
4. [4] X. Lv et al., “Study on two-phase flow dynamics in variable-diameter flow field and gas diffusion layer of poton exchange membrane fuel cells,” Fuel, vol. 392, no. January, p. 134911, 2025, doi: 10.1016/j.fuel.2025.134911.
5. [5] G. Abdul-Majeed, A. Al-Sarkhi, A. O. Mohmmed, and M. R. Hamoudi, “An empirical approach for predicting slug to pseudo-slug transition of air/water upward two-phase flow,” Exp. Comput. Multiph. Flow, vol. 6, no. 2, pp. 154–169, 2024, doi: 10.1007/s42757-023-0170-1.
6. [6] A. Arabi, Y. Salhi, Y. Zenati, E. K. Si-Ahmed, and J. Legrand, “Analysis of horizontal gas-liquid intermittent flow subregime transitions: Physical mechanisms and flow maps,” Exp. Comput. Multiph. Flow, vol. 7, no. 1, pp. 50–66, 2025, doi: 10.1007/s42757-023-0180-z.
7. [7] S. Li, T. Xue, and Z. Li, “A simple 3D reconstruction algorithm based on laser scanning: Research on flow characteristics of bubbles rising vertically in liquid phase,” Chem. Eng. Sci., vol. 276, no. January, p. 118796, 2023, doi: 10.1016/j.ces.2023.118796.
8. [8] D. Wu et al., “Heat exchanger design and performance evaluation for a high-temperature heat pump system under different two-phase correlations: 4E analysis,” Appl. Energy, vol. 384, no. January, 2025, doi: 10.1016/j.apenergy.2025.125492.

9. [9] C. D. Rakopouios and W. Murgatroyd, “Warme- und Stoffubertragung Heat Flux-Flow Coupling Effects in the Stability of Vapour Generators,” vol. 286, 1980.
10. [10] Tewari, P.K, Verma, R.K, Ramani, M.P.S, “Nucleate boiling in a thin film on a horizontal tube at atmospheric and sub atmospheric pressures,” Int. J. Heat Mass Transf., vol. 20, pp. 723–728, 1988.
11. [11] W. Yu, D. M. France, M. W. Wambsganss, and J. R. Hull, “Two-phase pressure drop, boiling heat transfer, and critical heat flux to water in a small-diameter horizontal tube,” Int. J. Multiph. Flow, vol. 28, no. 6, pp. 927–941, 2002, doi: 10.1016/S0301-9322(02)00019-8.
12. [12] L. K. H. Leung, D. C. Groeneveld, A. Teyssedou, and F. Aubé, “Pressure drops for steam and water flow in heated tubes,” Nucl. Eng. Des., vol. 235, no. 1, pp. 53–65, 2005, doi: 10.1016/j.nucengdes.2004.08.020.
13. [13] X. Li, R. Wang, R. Huang, and Y. Shi, “Numerical and experimental investigation of pressure drop characteristics during upward boiling two-phase flow of nitrogen,” Int. J. Heat Mass Transf., vol. 50, no. 9–10, pp. 1971–1981, 2007, doi: 10.1016/j.ijheatmasstransfer.2006.09.036.
14. [14] J. Moreno Quibén and J. R. Thome, “Flow pattern based two-phase frictional pressure drop model for horizontal tubes, Part II: New phenomenological model,” Int. J. Heat Fluid Flow, vol. 28, no. 5, pp. 1060–1072, 2007, doi: 10.1016/j.ijheatfluidflow.2007.01.004.
15. [15] Çomaklı Ö, Yılmaz M, Bedir Ö, Şahin B. “Isı Transferi İyileştirmesinin İki Fazlı Akış Kararsızlıklarına Etkisi,” Makina ve Mühendis, vol. 48, no. 565, p. 12, 2005, [Online]. http://www1.mmo.org.tr/resimler/dosya_ekler/2e7aaa88b48137a_ek.pdf?dergi=95
16. [16] G. Sotgia, P. Tartarini, and E. Stalio, “Experimental analysis of flow regimes and pressure drop reduction in oil-water mixtures,” Int. J. Multiph. Flow, vol. 34, no. 12, pp. 1161–1174, 2008, doi: 10.1016/j.ijmultiphaseflow.2008.06.001.
17. [17] B. A. Shannak, “Frictional pressure drop of gas liquid two-phase flow in pipes,” Nucl. Eng. Des., vol. 238, no. 12, pp. 3277–3284, 2008, doi: 10.1016/j.nucengdes.2008.08.015.
18. [18] S. Karagoz, S. Karsli, M. Yilmaz, and O. Comakli, “Density-wave flow oscillations in a water boiling horizontal tube with inserts,” J. Enhanc. Heat Transf., vol. 16, no. 4, pp. 331–350, 2009, doi: 10.1615/JEnhHeatTransf.v16.i4.20.
19. [19] M. Venkatesan, S. K. Das, and A. R. Balakrishnan, “Effect of diameter on two-phase pressure drop in narrow tubes,” Exp. Therm. Fluid Sci., vol. 35, no. 3, pp. 531–541, 2011, doi: 10.1016/j.expthermflusci.2010.12.007.
20. [20] G. Omeroglu, O. Çomaklý, S. Karagoz, and S. Karsli, “Comparison of the effects of different types of tube inserts on two-phase flow instabilities,” J. Enhanc. Heat Transf., vol. 20, no. 2, pp. 179–194, 2013, doi: 10.1615/JEnhHeatTransf.2013007708.
21. [21] C. Guo, T. Wang, X. Hu, and D. Tang, “Experimental and theoretical investigation on two-phase flow characteristics and pressure drop during flow condensation in heat transport pipeline,” Appl. Therm. Eng., vol. 66, no. 1–2, pp. 365–374, 2014, doi: 10.1016/j.applthermaleng.2014.02.028.
22. [22] M. K. Yeşilyurt, “İki fazlı akışlarda konik yayların boru içi ısı transferi ve akış kararsızlığı üzerindeki etkilerinin deneysel incelenmesi,” Yüksek Lisans Tezi, Fen Bilimleri Enstitüsü, Atatürk Üniversitesi, Erzurum, Türkiye, 2015.
23. [23] N. Adiguzel, A. Göcücü, “Experimental investigation of the effects of ring turbulators on heat transfer in two phase flow,” Iranian Journal of Science and Technology, Transactions of Mechanical Engineering, vol. 46, no. 3, pp. 829–838, 2022, doi: 10.1007/s40997-021-00472-y
24. [24] X. Zhu, C. Xu, M. Gu, and N. Wang, “Experimental Study on Two-Phase Countercurrent Flow Limitation in Horizontal Circular Pipes,” Energies, vol. 17, no. 9, 2024, doi: 10.3390/en17092081.
25. [25] J. Zhang et al., “Experimental investigations of gas–liquid two-phase flow in a horizontal mini pipe: Flow regime, void friction, and frictional pressure drops,” Phys. Fluids, vol. 35, no. 1, p. 13333, 2023.
26. [26] H. L. Cheon, H. Fyhn, A. Hansen, Ø. Wilhelmsen, and S. Sinha, “Steady-State Two-Phase Flow of Compressible and Incompressible Fluids in a Capillary Tube of Varying Radius,” Transp. Porous Media, vol. 147, no. 1, pp. 15–33, 2023, doi: 10.1007/s11242-022-01893-2.
27. [27] S. Karagoz, F. Afshari, O. Yildirim, and O. Comakli, “Experimental and numerical investigation of the cylindrical blade tube inserts effect on the heat transfer enhancement in the horizontal pipe exchangers,” Heat Mass Transf. und Stoffuebertragung, vol. 53, no. 9, pp. 2769–2784, 2017, doi: 10.1007/s00231-017-2021-8
28. [28] O. A. González-Estrada, S. Hernández, and G. González-Silva, “Modeling of Oil–Water Two-Phase Flow in Horizontal Pipes Using CFD for the Prediction of Flow Patterns,” Eng, vol. 5, no. 4, pp. 3316–3334, 2024, doi: 10.3390/eng5040173.
29. [29] A. O. Oyelade, J. O. Ehigie, K. Orolu, and A. O. Oyediran, “Dynamics of horizontal pipes conveying two phase flow with nonlinear boundary conditions,” Mech. Syst. Signal Process., vol. 217, no. May, p. 111520, 2024, doi: 10.1016/j.ymssp.2024.111520.
30. [30] S. Banerjee et al., “Two-Phase Crude Oil-Water Flow Through Different Pipes: An Experimental Investigation Coupled with Computational Fluid Dynamics Approach,” ACS Omega, vol. 9, no. 10, pp. 11181–11193, 2024, doi: 10.1021/acsomega.3c05290.
31. [31] C. N. Feng, K. Miyagawa, T. Kawahara, and Y. Katayama, “Frictional pressure drop of two-phase flow in a horizontal tube under low void fraction,” J. Phys. Conf. Ser., vol. 2707, no. 1, 2024, doi: 10.1088/1742-6596/2707/1/012142.
32. [32] J. Huang, F. Jiang, J. Huang, J. Dai, and J. Xiang, “Numerical study on the flow characteristics of oil-water annular flow under different vibration frequencies,” Chem. Eng. Res. Des., vol. 219, no. June, pp. 534–545, 2025, doi: 10.1016/j.cherd.2025.06.026.