Numerical analysis of heat transfer enhancement and flow structure of alternating oval tubes by considering different alternate angles under turbulent flow

Najafi Khaboshan, Hasan; Nazif, Hamid Reza

doi:10.22061/jcarme.2018.2974.1311

تعداد نشریات	13
تعداد شماره‌ها	237
تعداد مقالات	2,406
تعداد مشاهده مقاله	3,888,040
تعداد دریافت فایل اصل مقاله	2,826,464

	Numerical analysis of heat transfer enhancement and flow structure of alternating oval tubes by considering different alternate angles under turbulent flow
Journal of Computational & Applied Research in Mechanical Engineering (JCARME)
مقاله 4، دوره 9، شماره 2 - شماره پیاپی 18، فروردین 2020، صفحه 211-223 اصل مقاله (3.78 M)
نوع مقاله: Research Paper
شناسه دیجیتال (DOI): 10.22061/jcarme.2018.2974.1311
نویسندگان
Hasan Najafi Khaboshan؛ Hamid Reza Nazif^*
Department of Mechanical Engineering, Imam Khomeini International University, Qazvin, Iran
تاریخ دریافت: 17 مهر 1396، تاریخ بازنگری: 30 مهر 1397، تاریخ پذیرش: 05 آبان 1397
چکیده
In this research, the convective heat transfers of turbulent water fluid flow in alternating oval tubes is studied using computational fluid dynamics. The purpose of the study is to analyze the heat transfer enhancement and secondary internal flows under different alternate angles. Also, comparing the effect of two schemesfor the domain discretization to be used in the solution variables’ gradients on simulation results is investigated. The secondary flow causes an increase in the numbers of multi-longitudinal vortices (MLV) by changing the angle of pitches. These phenomena permit the cold fluid flow to stream in more paths from center to tube wall and better condition for mixing of fluids. Consequently, the heat transfer enhances by using the alternating oval tubes. However, forming the multi-longitudinal vortices causes an increase in pressure drop. Also, by raising the angle of pitches, the friction factor and the average of Nusselt number are amplified. It is also observed that the average heat transfer coefficient in the transition range is more than other areas. The mean Nussult numbers of this kind of tubes in the angles of 40, 60, 80, and 90 improved 7.77%, 14.6%, 16.93%, and 24.42%, respectively in comparison with the round tube. The performance evaluation criteria (PEC) for all alternating oval tubes under the constant inlet velocity boundary condition indicated that the highest value (PEC=1.09) had been obtained at the lowest Reynolds number (Re=10,000) in the alternating oval tube 90°.
کلیدواژه‌ها
Turbulent flow؛ Heat transfer؛ Friction factor؛ Nusselt number؛ Multi-longitudinal vortex؛ Alternating oval tube

مراجع
[1] H. Najafi Khaboshan, and H. R. Nazif, “Investigation of heat transfer and pressure drop of turbulent flow in tubes with successive alternating wall deformation under constant wall temperature boundary conditions”, Journal of the Brazilian Society of Mechanical Sciences and Engineering, Vol. 40, No. 2, p. 42, (2018). [2] J.-A. Meng, X.-G. Liang, Z.-J. Chen, and Z.-X. Li, “Experimental study on convective heat transfer in alternating elliptical axis tubes”, Experimental Thermal and Fluid Science, Vol. 29, No. 4, pp. 457-465, (2005). [3] A. R. Sajadi, S. Yamani Douzi Sorkhabi, D. Ashtiani, and F. Kowsari, “Experimental and numerical study on heat transfer and flow resistance of oil flow in alternating elliptical axis tubes”, International Journal of Heat and Mass Transfer, Vol. 77, pp. 124-130, (2014). [4] W.-L. Chen, and W.-C. Dung, “Numerical study on heat transfer characteristics of double tube heat exchangers with alternating horizontal or vertical oval cross section pipes as inner tubes”, Energy Conversion and Management, Vol. 49, No. 6, pp. 1574-1583, (2008). [5] J.-A. Zambaux, J.-L. Harion, S. Russeil, and P. Bouvier, “The effect of successive alternating wall deformation on the performance of an annular heat exchanger”, Applied Thermal Engineering, Vol. 90, pp. 286-295, (2015). [6] H. Najafi Khaboshan, and H. R. Nazif, “Heat transfer enhancement and entropy generation analysis of Al2O3-water nanofluid in an alternating oval cross-section tube using two-phase mixture model under turbulent flow”, Heat and Mass Transfer, Vol. 54, No. 10, pp. 3171-3183, (2018). [7] H. Najafi Khaboshan, and H. R. Nazif, “Numerical analysis on convective turbulent air in an alternating elliptical tube”, Modares Mechanical Engineering, Vol. 16, No. 13, pp. 5-8, (2016). [8] F. M. White, Viscous fluid flow, 2nd ed., McGraw-Hill, New York, (1991). [9] B. E. Launder, and D. B. Spalding, Lectures in mathematical models of turbulence, Academic Press, London, (1972). [10] H. Najafi Khaboshan, and H. R. Nazif, “The effect of multi-longitudinal vortex generation on turbulent convective heat transfer within alternating elliptical axis tubes with various alternative angles”, Case Studies in Thermal Engineering, Vol. 12, pp. 237-247, (2018). [11] M. Wolfshtein, “The velocity and temperature distribution in one-dimensional flow with turbulence augmentation and pressure gradient”, International Journal of Heat and Mass Transfer, Vol. 12, No. 3, pp. 301-318, (1969). [12] Z. Y. Guo, “A brief introduction to a novel heat-transfer enhancement heat exchanger”, internal report, Department of EMEMKLEHTEC, Tsinghua University, Beijing, China, (2003). [13] J. P. Van Doormaal, and G. D. Raithby, “Enhancements of the SIMPLE method for predicting incompressible fluid flows”, Numerical Heat Transfer, Vol. 7, No. 2, pp. 147-163, (1984). [14] A. J. Chorin, “Numerical solution of the Navier-Stokes equations”, Mathematics of Computation, Vol. 22, No. 104, pp. 745-762, (1968). [15] H. K. Versteeg, and W. Malalasekera, An introduction to computational fluid dynamics: the finite volume method, 2nd ed., Pearson Education, England, (2007). [16] D. G. Holmes, and S. D. Connell, “Solution of the 2D Navier-Stokes equations on unstructured adaptive grids”. Proc. of 9th Computational Fluid Dynamics Conference, p. 1932, (1989). [17] R. D. Rausch, J. T. Batina, and H. T. Y. Yang, “Spatial adaption procedures on unstructured meshes for accurate unsteady aerodynamic flow computation”. Proc. of 32nd Structures, Structural Dynamics, and Materials Conference, p. 1106, (1991). [18] R. F. Warming, and R. M. Beam, “Upwind second-order difference schemes and applications in aerodynamic flows”, AIAA Journal, Vol. 14, No. 9, pp. 1241-1249, (1976). [19] B. E. Launder, and D. B. Spalding, “The numerical computation of turbulent flows”, Computer Methods in Applied Mechanics and Engineering, Vol. 3, No. 2, pp. 269-289, (1974). [20] W.-L. Chen, Z. Guo, and C. o.-K. Chen, “A numerical study on the flow over a novel tube for heat-transfer enhancement with a linear Eddy-viscosity model”, International Journal of Heat and Mass Transfer, Vol. 47, No. 14, pp. 3431-3439, (2004). [21] B. S. Petukhov, T. F. Irvine, and J. P. Hartnett, Advances in heat transfer, Academic Press, New York, (1970). [22] V. Gnielinski, “New equations for heat and mass-transfer in turbulent pipe and channel flow”, International Chemical Engineering, Vol. 16, No. 2, pp. 359-368, (1976). [23] T. L. Bergman, A. S. Lavine, F. P. Incropera, and D. P. Dewitt, Fundamentals of heat and mass transfer, 7th ed., John Wiley & Sons, New Jersey, p. 545, (2011). [24] R. L. Webb, and N.-H. Kim, Principles of enhanced heat transfer, Taylor Francis, New York, (1994).
آمار تعداد مشاهده مقاله: 1,768 تعداد دریافت فایل اصل مقاله: 1,700

سامانه مدیریت نشریات علمی. طراحی و پیاده سازی از سیناوب

پیوندهای مفید

آمار

Numerical analysis of heat transfer enhancement and flow structure of alternating oval tubes by considering different alternate angles under turbulent flow