Numerical analysis of laminar and turbulent swirl flows

Sayısal çalışma laminer ve türbülanslı dönmeli akışların incelenmesi amacıyla yapılmıştır. Akış eşitlikleri sonlu hacim metodu ve $k-varepsilon$ türbülans modeli kullanılarak çözülmüştür. SIMPLE ve SIMPLEC algoritmaları basınç düzeltmeleri için karşılaştırmalı olarak kullanılmıştır. Konvektif terimler HDS yöntemi ile diskritize edilmiştir. Geliştirilen bilgisayar kodu ilk aşamada analitik çözümleri bilinen katı cisim dönmesi ve kaynak kuyu akışı problemleri ile test edilmiştir. Daha sonra türbülanslı boru akışı analiz edilmiştir. Son olarak da boru içinde azalan dönmeli akış ayrıntılı olarak incelenmiştir. Azalan dönmeli akışın pervane tipli dönme üretecinin yerleştirilmesi ile üretildiği farzedilmiştir. Bu durum için elde edilen sayısal sonuçlar deneysel sonuçlarla karşılaştırılmış ve iyi bir uyum gözlenmiştir.

Laminer ve türbülanslı dönmeli akışların sayısal analizi

A computational study is conducted to investigate laminar and turbulent swirl flows. The governing equations are solved using the $k-varepsilon$ model and the finite volume method. SIMPLE and SIMPLEC algorithms are comparatively used for pressure correction. Convective terms are discretized through the hybrid differencing scheme. At first, the computer code developed is checked against two problems of which analytical solutions are known from the existing literature, the solid body rotation and the source/sink flow. Then, turbulent flow in a pipe is analyzed. Finally, decaying turbulent swirl flow inside the pipe is examined in detail. Decaying swirl flow is assumed to be generated by the insertion of propeller type generators. The results obtained for this case have been also compared with those obtained experimentally and a good agreement is observed.

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1.Bali, T., Modeling of Heat Transfer and Fluid flow for decaying Swirl Flow in a Circular Pipe, Int. Comm. Heat Mass Transfer 25, 3, 349-358, 1998.
2.Bali, T. and Ayhan, T., Experimental Investigation of Propeller Type Swirl Generator for a Circular Pipe Flow, Int. Comm. Heat Mass Transfer 26, 1, 13-22, 1999.
3.Chang, K.C., Chen, C.S. and Uang, C.I., A Hybrid $k-varepsilon$ Turbulence Model of Recirculating Flow, Int. J. for Num. Meth. in Fluids 12, 369-382, 1991.
4.Doormall, J.P. and Raithby, G.D., Enhancement of the SIMPLE Method for Predicting Incompressible Fluid Flows, Numerical Heat Transfer 7, 147-163, 1984.
5.Hide, R., On source-sink flows in rotating fluid, J. Fluid Mech. 32, 737-745, 1968.
6.Hoekstra, A.J., Derksen, J.J. and Van Den Akker, H.E.A., An Experimental and Numerical Study of Turbulent Swirling Flow in Gas Cyclones, Chemical Engineering Science 54, 2055-2065, 1999.
7.Kitoh, D., Experimental study of turbulent swirling flow in a straight pipe, J. Fluid Mech. 225, 445-479, 1991.
8.Kreith, F. and Sonju, O.K., The Decay of a Turbulent Swirl in a Pipe, J. Fluid Mech. 22, 257-271, 1965.
9.Launder, B.E. and Spalding, D.B., The Numerical Computation of Turbulent Flows, Comp. Meth. Appl. Mech. Eng 3, 269-289, 1974.
10.Mondal, S., Datta, A. and Sarkar, A., Influence of Side Wall Expansion Angle and Swirl Generator on Flow Pattern in a Model Combustor Calculated with $k-varepsilon$ Model, Int. J. of Thermal Science 43, 9, 901-914, 2004. 11.Nikjooy, M. and Mongia, H.C., A 2nd Order Modeling Study of Confined Swirling Flow, Int. J. Heat Fluid Flow, 12, 1, 12-19, 1991.
12.Patankar, S.V., Numerical Heat Transfer and Fluid Flow, McGraw-Hill Book Co., New York, 1980.
13.Rodi, W., A Note on the Emprical Constant in the Kolmogorov-Prandtl Eddy Viscosity Expression, ASME J. Fluids Eng September, 386-389, 1975.
14.Sampers, W.F.J., Lamers, A.P.G.G. and Vansteenhoven, A.A., Analysis of Experimental and Numerical Results of a Turbulent Swirling Flow in a Tube, Chemical Engineering Communications, 125, 187-196, 1993.
15.Schlichting, H., Boundary Layer Theory (Seventh Ed.), McGraw-Hill Book Co., New York, 1979.
16.Senoo, Y. and Nagata, T., Swirl Flow in Long Pipes with Different Roughness, Bulletin ofJSME 15, 1514-1521,1972.
17.Smithberg, E. and Landis, F., Friction and Forced Convection Heat Transfer Characteristics in Tubes With Twisted Tape Swirl Generators, ASME Journal of Heat Transfer 86, 39-48, 1964.
18.Wang, P., Bai, X.S., Wessman, M., et al., Large Eddy Simulation and Experimental Studies of a Confined Turbulent Swirling Flow, Physics of Fluids 16, 9, 3306-3324,2004.
19.Yang, Z.Y., Large Eddy Simulation of Fully Developed Turbulent Flow in a Rotating Pipe, Int. J. for Numerical Methods In Fluids 33, 5, 681-694, 2000.