Work package 4.3 - Euler-Euler based simulation of two-phase flows in porous media and of bubbly flows
Principal Investigator: Dr. D. Lucas (Helmholtz-Zentrum Dresden-Rossendorf)
PhD Students: Thomas Ziegenhein, Kumar Subramanian (HZDR)
Main Scientific Goals:
This work package focuses on the qualification of CFD-models for the simulation of bubble columns and flows in foam structures(catalysts). The model development bases on the Euler-Euler approach.
The interaction between bubbles and liquid strongly depends on the bubble size. For this reason it is important to consider the bubble size distribution in an adequate simulation. A set of closure models for the momentum transfer between bubbles and the liquid, for bubble coalescence and breakup and for two-phase flow turbulence was defined based on physical considerations. This so-called baseline model for poly-disperse flows was widely validated for air-water pipe flows. One important scientific goal of this work package is to validate this setup for flows in different types of bubble columns.
|Figure 1 Simulation results for a laboratory-scale bubble column [bin Mohd Akbar, et al., Multiphase Sci. Technol., 24 (2013)] , gas volume fraction (left), axial liquid velocity (middle), and turbulent kinetic energy (right). Solid lines: simulation results, symbols: measured values. Only half of the column is shown.|
The two-phase flow in catalytic foam structures is strongly influenced by the interaction between the gas-liquid interface and the structure. Simulations are done based on the porous body approach. Closure models reflecting the above mentioned interaction have to be developed. Starting point are existing closures for trickle bed reactors. One important task for the extension of these models for foam structures is the characterisation of structural parameters of the ceramic foam structures. This is done in close cooperation with other work packages within the Helmholtz Energy Alliance, e.g. the simulation results will be validated with Tomographic studies performed in the work package 3.1.
|Figure 2 REM image of 10 ppi foam|
- T. Ziegenhein, R. Rzehak, E. Krepper, D. Lucas, Numerical Simulation of Polydispersed Flow in Bubble Columns with the Inhomogeneous Multi-Size-Group Model, Chemie Ingenieur Technik, 2013, 85, No. 7, 1080–1091.
- T. Ziegenhein, D. Lucas, R. Rzehak, E. Krepper, Closure relations for CFD simulation of bubble columns, 8th International Conference on Multiphase Flow , ICMF 2013, Jeju, Korea, May 26 - 31, 2013
- K. Subramanian, M. Schubert, E.Krepper, D.Lucas, U. Hampel (2013), Three-dimensional simulation of multiphase flows in porous solid foam structures, Poster, International conference on Porous media (Interpore), Prague, 21. - 24.May 2013
- K. Subramanian, M. Schubert, D.Lucas, U. Hampel (2014), Closures for simulation of Gas-Liquid flows in Solid foam structures, Oral Talk, International Symposium on Chemical Reaction Engineering (ISCRE 23) , Bangkok, Thailand, 07 – 10th September 2014
T. Ziegenhein, R. Rzehak, D. Lucas, Transient simulation for large scale flow in bubble columns, Chemical Engineering Science, 2015, 122, 1-13. (Preprint: https://www.hzdr.de/db/Cms?pOid=42965)