Bubble-induced turbulence (BIT)
The turbulence of the liquid phase influences the local distribution of the dispersed phase, bubble coalescence and breakup and other important flow characteristics. Because of the importance of turbulence it is necessary to consider its modiﬁcation by bubbles. The conservation equation for the turbulent kinetic energy (TKE) of the two-phase flow besides the single-phase-like terms contains an additional interfacial term representing the interfacial energy transfer between phases.
The TKE Budgets from direct numerical simulations (DNS) of disperse vertical bubbly channel flows (done at TU Dresden, Institute of Fluid Mechanics) are used to develop a new model for bubble-induced turbulence (BIT) in the Euler-Euler (EE) framework. Appropriate time and length scales for the BIT are determined and the corresponding source terms in the Shear Stress Transport Model are derived from the data. This yields a closure which can be readily used in any similar two-equation Reynolds-averaged Navier-Stokes (RANS) model (see baseline definition or Ma et al., 2017). The model is validated by dedicated Euler-Euler simulations and is part of the baseline model for poly-disperse flows.
T. Ma, C. Santarelli, T. Ziegenhein, D. Lucas and J. Fröhlich,
Direct numerical simulation–based Reynolds-averaged closure for bubble-induced turbulence.
Physical Review Fluids 2, 034301, 2017
T. Ziegenhein, R. Rzehak, T. Ma and D. Lucas,
A unified approach for modeling uniform and non-uniform bubbly flows.
The Canadian Journal of Chemical Engineering, 96 (1), 170-179, 2017
T. Ma, T. Ziegenhein, D. Lucas and J. Fröhlich,
Large eddy simulations of the gas-liquid flow in a rectangular bubble column.
Nuclear Engineering and Design, 299, 146-153, 2016
T. Ma, D. Lucas, T. Ziegenhein, J. Fröhlich and N.G. Deen,
Scale-adaptive simulation of a square cross-sectional bubble column.
Chemical Engineering Science, 131, 101-108, 2015
T. Ma, T. Ziegenhein, D. Lucas, E. Krepper and J. Fröhlich,
Euler-Euler Large eddy simulation for dispersed turbulent bubbly flows.
International Journal of Heat and Fluid Flow, 56, 51-59, 2015
T. Ziegenhein, R. Rzehak and D. Lucas,
Transient simulation for large scale flow in bubble columns.
Chemical Engineering Science, 122, 1-13, 2015