The HZDR multiphase addon contains additional code for the open-source CFD software OpenFOAM, released by The OpenFOAM Foundation. The developments are dedicated to the numerical simulation of multiphase flows, in particular to the multi-field two-fluid model (Euler-Euler method). Within the OpenFOAM library the multiphaseEulerFoam framework is used for this type of simulation. The addon contains a modified multiphaseEulerFoam named HZDRmultiphaseEulerFoam with the full support of the HZDR baseline model set for polydisperse bubbly flows according to Liao et al. (Chem Eng Sci, 2019, Vol. 202, 55-69). In addition a solver dedicated to a hybrid modelling approach (dispersed and resolved interfaces, Meller et al., Int J Numer Meth Fluids. 2021, Vol. 93, 748-773) named cipsaMultiphaseEulerFoam is provided with the addon. This solver has an interface to the multiphaseEulerFoam framework and utilizes all available interfacial models of it.

General enhancements

modified turbulent wall functions of Menter according to Rzehak and Kriebitzsch (Int J Multiphase Flow, 2015, Vol. 68, 135-152)
dynamic time step adjustment via PID controller

HZDRmultiphaseEulerFoam

bubble induced turbulence model of Ma et al. (Phys Rev Fluids, 2017, Vol. 2, 034301)
drag model of Ishii and Zuber (AIChE Journal, 1979, Vol. 25, 843-855) without correction for swarm and/or viscous effects
wall lubrication of Hosokawa et al. (ASME Joint US-European Fluids Engineering Division Conference, 2002)
additional breakup and coalescence models for class method according to Liao et al. (Chem Eng Sci, 2015, Vol. 122, 336-349)
degassing boundary condition (fvModel)
lift force correlation of Hessenkemper et al. (Int J Multiphase Flow, 2021, Vol. 138, 103587)
aspect ratio correlation of Ziegenhein and Lucas (Exp. Therm. Fluid Sci., 2017, Vol. 85, 248–256)
real pressure treatment via explicit turbulent normal stress according to Rzehak et al. (Nucl Eng Des., 2021, Vol. 374, 111079)
configuration files and tutorials for easy setup of baseline cases

cipsaMultiphaseEulerFoam

morphology adaptive modelling framework for predicting dispersed and resolved interfaces based on Eulerian multi-field two-fluid model
compact momentum interpolation method according to Cubero et al. (Comput Chem Eng, 2014, Vol. 62, 96-107), including virtual mass
numerical drag according to Strubelj and Tiselj (Int J Numer Methods Eng, 2011, Vol. 85, 575-590) to describe resolved interfaces in a volume-of-fluid like manner
n-phase partial elimination algorithm for momentum equations to resolve strong phase coupling (Meller et al., Int J Numer Meth Fluids. 2021, Vol. 93, 748-773)
free surface turbulence damping for k-ω SST (symmetric and asymmetric damping, Frederix et al.,  Nucl Eng Des, 2018, Vol. 333, 122-130)
sub-grid scale modelling framework:

    additional LES models for the unclosed convective sub-grid scale term
    closure models for sub-grid surface tension term


configuration files and tutorials for easy setup of hybrid cases

This work was supported by the Helmholtz European Partnering Program in the project "Crossing borders and scales (Crossing)"

{"references": ["Meller, R., Schlegel, F., & Lucas, D. (2020). Basic verification of a numerical framework applied to a morphology adaptive multifield two\u2010fluid model considering bubble motions. International Journal for Numerical Methods in Fluids.", "Rzehak, R., Liao, Y., Meller, R., Schlegel, F., Lehnigk, R., & Lucas, D. (2021). Radial pressure forces in Euler-Euler simulations of turbulent bubbly pipe flows. Nuclear Engineering and Design, 374, 111079.", "H\u00e4nsch, S., Evdokimov, I., Schlegel, F., & Lucas, D. (2021). A workflow for the sustainable development of closure models for bubbly flows. Chemical Engineering Science, 116807.", "Tekav\u010di\u010d, M., Meller, R., & Schlegel, F. (2021). Validation of a morphology adaptive multi-field two-fluid model considering counter-current stratified flow with interfacial turbulence damping. Nuclear Engineering and Design, 379, 111223."]}