Numerical Analysis of Energy Loss Coefficient in Pipe Contraction Using ANSYS CFX Software

Kourosh Nosrati, Ahmad Tahershamsi, Seyed Heja Seyed Taheri


The purpose of this study is the numerical analysis of energy loss coefficient in pipe contraction using ANSYS CFX software. To this end, the effect of the dimensionless parameters of Euler number, Reynolds number, and relative roughness on energy loss coefficient has been investigated and eventually an overall formula to determine the energy loss coefficient in these transitions has been provided. In order to solve the fluid turbulence equations in the pipe, standard K-Epsilon model has been used. For this purpose, first the geometry of pipe transitions was designed in 3-D, using Solid Works software, and then the transitions were meshed by ANSYS MESHING. The initial simulation of transitions including boundary conditions of outlet, inlet and wall, was carried out by a pre-processor called CFX-PRE. Furthermore, to solve the equations governing the fluid flow in the pipes (Navier-Stokes equations) the CFX-SOLVER was used. And finally, the results were extracted using a post-processor called CFD-POST.

The results indicated that the energy loss coefficient, contrary to the findings of previous researchers, is not only related to transition geometry, but also is dependent on the Reynolds number, relative roughness of the wall and Euler number. By increasing the Reynolds Number and turbulence of fluid flow in transitions, the energy loss coefficient is reduced. Moreover, by increasing the relative roughness in the transition’s wall the energy loss coefficient is reduced. The increase in pressure fluctuation causes the increase of Euler number which leads to the linear increase of energy loss coefficient.


Energy Loss Coefficient; Pipe Contraction; Standard K-Epsilon; ANSYS CFX; ANSYS Meshing.


Weisbach J. “Die Experimental Hydraulic”, Freiberg, Germany: Engelhard. (1855).

Liaqat Ali Hussain. ”The Experimental and Theatrical Analysis of Pipe Contraction Flow Fields", MPhil. Thesis, Kingston Polytechnic”. (1990)Udwadia, F.E. and Trifunac, M.D.

Kays, W. M. “Loss Coefficients for Abrupt Change in Flow Cross Section with Low Reynolds Number Flow in Single and Multiple Tube System”. Technical Report No. 9. No. NP-3901; U-9356. Stanford Univ. (1950).

Gianni Astarita and Guido Greco” Excess Pressure Drop in Laminar Flow through Sudden Contraction. Newtonian Liquids” Industrial & Engineering Chemistry Fundamentals 7 (1), 27-31. (1968).

Gerami-Tajabadi, H. “The determination of pressure loss coefficients for an incompressible turbulent flow through pipe contractions”, MPhil. Thesis, Kingston Polytechnic. (1985).

Prions, P. & Goulash, A. “Flow characteristics in a pipe with a gradual contraction. Journal of Hydraulic Research”, 31(5), 587-600. (1993).

E. S. D. U. “Pressure losses in f low through a sudden contraction of duct area”, Data Sheet 78007. (1977).

Durst, F. and T. Loy. “Investigations of laminar flow in a pipe with sudden contraction of cross sectional area. Computers & fluids” 13.1: 15-36. (1985).

Hooper, W. B. “Calculate head loss caused by change in pipe size”. Chemical Engineering, 95(16), 89. (1988).

Benedict, R. P. and J. S. Wyler. “A generalized discharge coefficient for differential pressure type fluid meters”. Journal of Engineering for Power 96.4 (1974): 440-448.

Streeter, Victor. ”Fluids Mechanics”, Mac Graw-Hill Inc. 4th ed. (1966).

John F. Newton “Pressure Loss in PVC Pipe Fittings Caused by Connection Gaps and Glue Beads” A thesis Master of Science in Civil and Environmental Engineering, Utah State University), (2005).

ANSYS CFX-Solver Modeling Guide, Release 15.0, November. (2013).

King, H. W. C. Wisler. And Woodburn, J.G. “Hydraulics 5th” New York, pp 206-209. (1948).

Zarrati, Amirreza “Fluid mechanic and hydraulic laboratory” 2th Ed, (2012).

Streeter, Victor. "Fluids Mechanics ,Mac Graw-Hill Inc. 4th Ed, (1966).

Kourosh, Nosrati “Numerical Analysis of Energy Loss Coefficient in Pipe Contraction Using ANSYS CFX Software” Master thesis, Department of Civil Engineering and Environmental Amirkabir university of Tehran (Tehran Polytechnic), (2016).

Satish, G. et al. "Comparison of flow analysis of a sudden and gradual change of pipe diameter using fluent software. Int. J. Res. Eng. Techno 2.12: 41-45. (2013)

Zhao, H.Y. Jia, X.S. Yang, S.M. et al. Numerical Simulation of Separation Flow Filed of Sudden Expansion Tube. Scientific Technology and Engineering, 9, 5238-5240. (2009).

Zhou, Z.D. Wei, C.Z. Sun, M.Y. et al. Numerical Simulation of Flow Form of Sudden Expansion Tube. Scientific Technology and Engineering, 12, 7983-7985. (2012).

Li, Yinpeng, Changjin Wang, and Mingda Ha. "Experimental Determination of Local Resistance Coefficient of Sudden Expansion Tube. Energy and Power Engineering 7.04: 154. (2015).

Full Text: PDF


  • There are currently no refbacks.

Copyright (c) 2017 Kourosh Nosrati, Ahmad Tahershamsi, Seyed Heja Seyed Taheri

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.