Fundamental analysis of gas and liquid phase dynamics
The complex flow and mixing behavior in bubble columns is often described via gas holdup, bubble size and liquid circulation velocity. The bubble size distribution and its spatiotemporal evolution is a key factor for the estimation of heat and mass transfer coefficients. Other crucial hydrodynamic parameters of bubble columns are local liquid velocity and the degree of turbulence. For example, changes in the bubble size distribution due to breakup and coalescence events are driven by the liquid phase turbulence.
Experimental analyses in bubble columns using advanced noninvasive imaging techniques, namely Ultrafast X-ray Computed Tomography (UXCT @ HZDR) and Radioactive Particle Tracking (RPT @ IIT Delhi), in a time-resolved manner were performed, where each data set provides complimentary information to the other.
Thereby, experimental data for gas and liquid phase dynamics were generated covering gas holdup, bubbles size, liquid velocity and turbulent kinetic energy.
Based on these data, bubble column hydrodynamics could be comprehensively characterized, including clustering by means of Voronoï analysis (utilizing bubble positions within a hybrid Eulerian framework) as well as flow regime transition via extraction of information and reconstruction entropies. Eventually, the obtained experimental data provide unique and valuable validation cases for numerical models of bubble columns.
IIT Delhi, India
European Research Council (ERC Starting Grant, Grant Agreement No. 307360)
- S. Azizi, A. Yadav, Y.M. Lau, U. Hampel, S. Roy, M. Schubert (2016)
On the experimental investigation of gas-liquid flow in bubble columns using ultrafast X-ray tomography and radioactive particle tracking.
Chemical Engineering Science, DOI: 10.1016/j.ces.2017.02.015.
- S. Nedeltchev, U. Hampel, M. Schubert (2016).
Extraction of information and reconstruction entropies from ultrafast X-ray tomography data in a bubble column.
Chemical Engineering Science, DOI: 10.1016/j.ces.2017.03.020.
- Y.M. Lau, K. Müller, S. Azizi, M. Schubert (2016).
Voronoï analysis of bubbly flows via ultrafast X-ray tomographic imaging.
Experiments in Fluids 57, 3, 35, 1-12.
- F. Möller, T. Seiler, Y.M. Lau, M. Weber, M. Weber, U. Hampel, M. Schubert (2017).
Performance comparison between different sparger plate orifice patterns: Hydrodynamic investigation using ultrafast X-ray tomography.
Chemical Engineering Journal 316, 857-871.
- Y.M. Lau, M. Schubert (2014).
Bubble size and velocity measurements in bubble columns using ultrafast X-ray tomography.
AIChE Annual Meeting, Atlanta, United States, 16-21 November 2014, pp. 50-52.