Three Dimensional Numerical Analysis of Two Phase Flow Separation Using Swirling Fluidics

M. M. Rahman, Nobuatsu Tanaka, S. Yokobori, S. Hirai

Department of Mechanical Engineering, Faculty of Engineering, Ibaraki University, Hitachi, Japan.
Department of Nuclear Safety Engineering, Faculty of Engineering, Tokyo City University, Tokyo, Japan.
Energy Institute, Atomic Energy Research Establishment, Dhaka, Bangladesh.

DOI: 10.4236/epe.2013.54030                

Abstract

Vapor-water two phase flow separation in pressure vessel of nuclear power plants is accomplished with swirl motion using vanes. In order to reduce separation pressure loss and to make it economic, a new type of low cost simplified innovative separator using lattice core configuration is proposed where swirling is caused by the orthogonal driving flow. The performance of the separator has been assessed numerically with the commercial CFD code FLUENT 14.0. The numerical analysis is compared with the experiment. The geometry and flow conditions are chosen according to the experiment. In the analysis, standard k – e and realizable k – e turbulence models are implemented. The prediction of maximum air void fraction with realizable k – e model was almost the same as input air void fraction but the void fraction computed by standard k – e model was compared better with the experimental results than the realizable k – e model. Some discrepancies in flow pattern between the experimental and simulation results are observed which might be due to the difference of nozzle shape. However, a more detailed model is necessary to arrive at the final conclusion.

Keywords

Two Phase Flow; Separation; Nuclear Power Plants; Swirling; CFD

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Y. Saito, G. Aoyama, H. Souma and T. Nakao, “Analysis of Droplet Behavior in BWR Separator,” Journal of Nu clear Science and Technology, Vol. 31, No. 4, 1994, pp. 349-335. doi:10.1080/18811248.1994.9735160
[2]	S. Hirai and S. Yokobori, “Innovative Two Phase Flow Separation Using Swirling Fluidics,” Proceedings of the Annual Meeting of Japan Society of Fluid Mechanics, Kochi, September 2012 (in Japanese).
[3]	S. Hirai, “Innovative Two Phase Flow Separation Using Swirling Fluidics,” Master Thesis, Tokyo City University, Tokyo, 2012 (in Japanese).
[4]	ANSYS FLUENT 14.0, 2008. http://www.ansys.com/Prodcts/Simulation+Technoloy/Fluid+Dynamics/ Fluid+Dynamics+Products/ANSYS+Fluent
[5]	B. E. Launder and D. B. Spalding, “Lectures in Mathematical Models of Turbulence,” Academic Press, London, 1972.
[6]	T. H. Shih, W. W. Liou, A. Shabbir, Z. Yang and J. Zhu, “A New k –ε Eddy-Viscosity Model for High Reynolds Number Turbulent Flows—Model Development and Validation,” Computers Fluids, Vol. 24, No. 3, 1995, pp. 227-238. doi:10.1016/0045-7930(94)00032-T
[7]	W. C. Reynolds, “Fundamentals of Turbulence for Turbulence Modeling and Simulation,” Lecture Notes for Von Karman Institute, Agard Report No. 755, 1987