Author(s) Se Youl Won, Jae Gon Lee, Jun Seok Yang

Affiliation(s)
Central Research Institute, Korea Hydro & Nuclear Power Co., Ltd., Daejeon, Korea.

ABSTRACT

This study presents the numerical evaluation about the impact of flow disturbance near the intrados and extrados regions of the 90 degree bended elbow using CFX for several practical cases where the 90 degree bended upward elbow is located in a proximity to the butterfly valve and the butterfly valve open angle is changed. For the change of a butterfly valve open angle from 60% to 100% and the increase of the distance between a valve and a 90 degree bended elbow, the effect of FAC (Flow-Accelerated Corrosion) in the 90 degree bended elbow may be neglected because the value and distribution of the velocity and shear stress is rapidly decreased comparing with the present status installed in an industry, and the data of 100% valve open (Case 3) and L/D ≈ 5 (Case 4) are very good agreement comparing with the reference data, L/D ≈ 8 (Case 2). The reasons are that flow already maintains a fully developed condition and a steady state in spite of less distance than the reference case, L/D = 8. Therefore, smooth flow fields have approached at a 90 degree bended elbow. Then, the effect of shear stress and vortex is hardly investigated around the intrados area of 90 degree bended elbow.

KEYWORDS
Flow Disturbance, Shear Stress, 90 Degree Bended Elbow, Butterfly Valve, FAC

Cite this paper
Won, S. , Lee, J. and Yang, J. (2014) The Effect of the Variation of the Downstream Region Distance and Butterfly Valve Angle on Flow Characteristics in a 90 Degree Bended Elbow. Modern Mechanical Engineering, 4, 133-143. doi: 10.4236/mme.2014.43013.

References
[1]   Addy, A.L., Morris, M J. and Dutton, J.C. (1985) An Investigation of Compressible Flow Characteristics of Butterfly Valve. ASME Journal of Fluid Engineering, 107, 512-517.
http://dx.doi.org/10.1115/1.3242522

[2]   Eom, K. (1988) Performance of Butterfly Valves as a Flow Controller. ASME Journal of Fluid Engineering, 110, 16-19.
http://dx.doi.org/10.1115/1.3243503

[3]   Morris, M.J. and Dutton, J.C. (1989) Aerodynamics Torque Characteristics of Butterfly Valves in Compressible Flow. ASME Journal of Fluids Engineering, 111, 392-399.
http://dx.doi.org/10.1115/1.3243658

[4]   Park, S.W. and Lee, S.W. (2000) Three-Dimensional Flow Characteristics in the Downstream Region of a ButterflyType Valve Used in Air-Conditioning System. KSME Journal B, 24, 260-269.

[5]   Barton, N.A. (2003) Erosion in Elbow in Hydrocarbon Production System: Review Document. Health & Safety Executive: Research Report 115.

[6]   EPRI (1998) Application Guide for Motor-Operated Valves in Nuclear Power Plant. EPRI TR-106563-V2.

[7]   Danbon, F. and Solliec, C. (2000) Aerodynamic Torque of a Butterfly Valve: Influence of an Elbow on the Time-Mean and Instantaneous Aerodynamic Torque. ASME Journal of Fluids Engineering, 122, 337-377.
http://dx.doi.org/10.1115/1.483262

[8]   Ansys (2005) CFX-10: User’s Manual Version 10, USA.