Document Type : Research Paper


Faculty of Mechanical Engineering, University of Guilan, Rasht, Iran


In this paper, numerical investigation of upward two phase flow of air-water has been studied. Different conditions of flow regimes including annular, wispy annular, slug, churn and bubbly are simulated based on Hewitt and Roberts map, and a good agreement between the experimental data of the map and the numerical simulation has been observed. Accordingly, a proper CFD model in CFD software of Fluent with the required User Defined Function (UDF) has been obtained to simulate two phase flows of fluids with large density ratio in vertical tubes. The simulation is carried out with the volume of fluid (VOF) method and piecewise interface calculation (PLIC) algorithm for tracking the interface for the annular, wispy annular, churn and slug flow regimes and drift flux model for bubbly with proper selection of computational cell and time step sizes. Furthermore, water and air momentum fluxes have been changed and the changes to the flow patterns are studied.

Graphical Abstract

Numerical investigation of upward air-water annular, slug and bubbly flow regimes


Main Subjects

[1]       O. Baker, “Simultaneous flow of oil and gas”, oil Gas J., Vol. 53, pp.185–195, (1954).


[2]       A. W. Bennett, A. W. Hewitt, H. A. Kearsey, “Flow visualization studies of boiling at high pressure”, P. I. Mech. Eng, Vol. 180, pp.1–11, (1965).


[3]       G. F. Hewitt and D. N. Roberts, “Studies of two-phase flow patterns by simultaneous X-ray and flash photography”, UKAEA Report AERE M2159, (1969).


[4]       P. J. Waltrich, G. Falcone, J. R. Barbosa, “Axial development of annular, churn and slug flows in a long vertical tube”, Int. J. Multiphase Flow, Vol. 57, pp.38–48, (2013).


[5]       H. Shaban and S. Tavoularis, “Identification of flow regime in vertical upward air water pipe flow using differential pressure signals and elastic maps”, Int. J. Multiphase Flow, Vol. 61, pp.62–72, (2014).


[6]       M. R. Ansari and R. Azadi, “Effect of diameter and axial location on upward gas liquid two-phase flow patterns in intermediate-scale vertical tubes”, Ann. Nucl. Energy, Vol. 94, pp.530–540, (2016).


[7]       C. Y. Yang and C. C. Shieh, “Flow pattern of air–water and two-phase R-134a in small circular tubes”, Int. J. Multiphase Flow, Vol. 27, NO. 7, pp.1163–1177, (2001).


[8]       L. A. Kozulin and V. V. Kuznetsov, “Statistical Characteristics of two-phase gas liquid flow in a vertical microchannel”, Journal of Applied Mechanics and Technical Physics, Vol. 52, NO. 6, pp.956–964, (2011).


[9]       M. Milan, N. Borhani, J. R., Thome, “Adiabatic vertical downward air-water flow pattem map: Influence of inlet device, flow development length and hysteresis effects”, Int. J. Multiphase Flow, Vol. 56, pp.126–137, (2013).


[10]     J. D. Talley, T. Worosz, S. Kim, J. R. Buchanan, “Characterization of horizontal air-water two-phase flow in a round pipe part I: Flow visualization”, Int. J. Multiphase Flow, Vol. 76, pp.212–222, (2015).


[11]     L. Chen, Y. S. Tian, T. G. Karayiannis, “The effect of tube diameter on vertical two-phase flow regimes in small tubes”, Int. J. Heat Mass Tran., Vol. 49, pp.4220–4230, (2006).


[12]     M. Zhang, L. m. Pan, P. Ju, X. Yang, M. Ishii, “The mechanism of bubbly to slug flow regime transition in air-water two phase flow: A new transition criterion”, Int. J. Heat Mass Tran., Vol. 108, pp.1579–1590, (2017).


[13]     Z. Li, G. Wang, M. Yousaf, X. Yang, M. Ishii, “Flow structure and flow regime transitions of downward two-phase flow in large diameter pipes”, Int. J. Heat Mass Tran., Vol. 118, pp.812–822, (2018).


[14]     P. Hanafizadeh, S. Ghanbarzadeh, M. H. Saidi, “Visual technique for detection of gas–liquid two-phase flow regime in the airlift pump”, J. Petrol. Sci. Eng., Vol. 75, pp.327–335, (2011).


[15]     T. Taha, Z. F. Cui, “CFD modelling of slug flow in vertical tubes”, Chemical Engineering Science, Vol. 61, NO. 2, pp.676–687, (2006).


[16]     C. K. De Schepper, G. J. Heynderickx, G. B. Marin, “CFD modeling of all gas–liquid and vapor–liquid flow regimes predicted by the Baker chart”, Chem. Eng. J., Vol. 138, pp.349–357, (2008).


[17]     Th. Frank, P. J. Zwart, E. Krepper, H. –M. Prasser, D. Lucas, “Validation of CFD models for mono- and polydisperse air–water two-phase flows in pipes”, Nuclear Engineering and Design, Vol. 238, pp.647–659, (2008).


[18]     N. Shao, W. Salman, A. Gavriilidis, P. Angeli, “CFD simulations of the effect of inlet conditions on Taylor flow formation”, International Journal of Heat and Fluid Flow, Vol. 29, NO. 6, pp.1603–1611, (2008).


[19]     P. Wei, K. Zhang, W. Gao, L. Kong, R. Field, “CFD modeling of hydrodynamic characteristics of slug bubble flow in a flat sheet membrane bioreactor”, Journal of Membrane Science, Vol. 445, pp.15–24, (2013).


[20]     R. Rahimi, E. Bahrarni far, M. Mazarei Sotoodeh, “The indication of two phase flow pattern and slug characteristics in a pipeline using CFD method”, Gas Processing Journal, Vol. 1, pp.70–87, (2013).


[21]     J. Gregorc and I. Žun, “Inlet conditions effect on bubble to slug flow transition in mini-channels”, Chem. Eng. Sci., Vol. 102, pp.106–120, (2013).


[22]     H. Pouraria, J. K. Seo, J. K. Paik, “Numerical modeling of two–phase oil–water slow patterns in a subsea pipeline”, Ocean Eng., Vol. 115, pp.135–148, (2016).


[23]     J. U. Brackbill, D. B. Kothe, C. Zemach, “A Continuum Method for Modeling Surface Tension”, J. Comput. Phys., Vol. 100, NO. 2, pp.335–354, (1992).


[24]     M. Manninen, V. Taivassalo, S. Kallio, On the mixture model for multiphase flow, VTT Publications 288, Technical Research Centre of Finland, (1996).


[25]     G. Tryggvason, B. Bunner, A. Esmaeeli, D. Juric, N. Al-Rawahi, “A Front Tracking Method for the Computations of Multiphase Flow”, J. Comput. Phys., Vol. 169, pp.708–759, (2001).


[26]     M. Sussman, P. Smereka, S. Osher, “A Level Set Approach for Computing Solutions to Incompressible Two-Phase Flow”, J. Comput. Phys., Vol. 114, pp.146–159, (1995).


[27]     D. Jacqmin, “Calculation of Two-Phase Navier–Stokes Flows Using Phase Field Modeling”, J. Comput. Phys., Vol. 155, pp.96–127, (1999).


[28]     L. D. Youngs, Time-dependent multi-material flow with large fluid distortion, in Numerical Methods for Fluid Dynamics, Academic Press, New York., (1982).


[29]     J. Li, “Calcul d’interface affin''e par morceaux (piecewise linear interface calculation)”, C.R. Acad. Sci. Paris S’erie IIb: Paris, Vol. 320, pp.391–396, (1995).


[30]     T. H. Shih, W. W. Liou, A. Shabbir, Z. Yang, J. Zhu, “A new k-epsilon eddy viscosity model for high Reynolds number turbulent Flows - model development and validation”, COMPUT FLUIDS, Vol. 24, pp.227–238, (1995).


[31]     J. G. Collier, J. R. Thome, Convective boiling and condensation, 3rd ed., Clarendon Press, Oxford, pp. 48-68, (1994).