Real time magnetic resonance imaging and numerical modelling of gas-solid hydrodynamics in vibrated bubbling fluidized beds
Publikationstyp
Conference Presentation
Date Issued
2025
Sprache
English
Author(s)
Citation
Jahrestreffen der DECHEMA/VDI-Fachgruppen Mischvorgänge, Hochdruckverfahrenstechnik und Mehrphasenströmungen 2025
Gas-solid fluidized beds are widely utilized in various process engineering applications for their enhanced heat and mass transfer rates. Vibration can improve the performance of fluidized beds by enhancing fluidization of cohesive particles, breaking agglomerates, improving mixing, and enhancing heat transfer in drying [1].
Studying hydrodynamics is challenging due to the chaotic nature of fluidized beds. The addition of vibration makes the dynamics even more complex, and our understanding of their hydrodynamics remains limited, especially in three-dimensional (3D) systems. Tomographic techniques, such as Magnetic Resonance Imaging (MRI) [2], have emerged as indispensable tools for the non-invasive and spatially resolved analysis of 3D beds.
This work investigates the hydrodynamics of 3D beds, with and without vibration, using real-time MRI with a unique 3T vertical MRI scanner. The vertical orientation of the magnet enables the measurement of samples up to 400 mm in diameter and several meters in height. An electrodynamic shaker generates vertical sinusoidal acceleration, with vibrations transmitted to the bed via glass fiber-reinforced tubes. The MRI system is elevated from the ground and offers a unique radiofrequency shielding, making it possible to place the electrodynamic shaker in axis. Properties such as bubble size, rise velocity and the influence of particle properties are investigated. Furthermore, complex phenomena, such as dynamically structured bubbling [3], can be studied in 3D systems.
Numerical simulations, such as CFD-DEM, which combines computational fluid dynamics and the discrete element method, offer valuable insights into hydrodynamics. In collaboration with the Institute of Solids Process Engineering and Particle Technology, MRI data is compared with CFD-DEM results to validate drag force models and coarse-graining approaches.
The project is financially supported by the German Research Foundation (DFG) under project number 471615686.
[1] Guo, Q. et al., Current Opinion in Chemical Engineering, 2023, 100977
[2] Penn, A. et al., Science Advances, 2017, 117-123
[3] Guo, Q. et al., PNAS, 2021, 35, e2108647118
Studying hydrodynamics is challenging due to the chaotic nature of fluidized beds. The addition of vibration makes the dynamics even more complex, and our understanding of their hydrodynamics remains limited, especially in three-dimensional (3D) systems. Tomographic techniques, such as Magnetic Resonance Imaging (MRI) [2], have emerged as indispensable tools for the non-invasive and spatially resolved analysis of 3D beds.
This work investigates the hydrodynamics of 3D beds, with and without vibration, using real-time MRI with a unique 3T vertical MRI scanner. The vertical orientation of the magnet enables the measurement of samples up to 400 mm in diameter and several meters in height. An electrodynamic shaker generates vertical sinusoidal acceleration, with vibrations transmitted to the bed via glass fiber-reinforced tubes. The MRI system is elevated from the ground and offers a unique radiofrequency shielding, making it possible to place the electrodynamic shaker in axis. Properties such as bubble size, rise velocity and the influence of particle properties are investigated. Furthermore, complex phenomena, such as dynamically structured bubbling [3], can be studied in 3D systems.
Numerical simulations, such as CFD-DEM, which combines computational fluid dynamics and the discrete element method, offer valuable insights into hydrodynamics. In collaboration with the Institute of Solids Process Engineering and Particle Technology, MRI data is compared with CFD-DEM results to validate drag force models and coarse-graining approaches.
The project is financially supported by the German Research Foundation (DFG) under project number 471615686.
[1] Guo, Q. et al., Current Opinion in Chemical Engineering, 2023, 100977
[2] Penn, A. et al., Science Advances, 2017, 117-123
[3] Guo, Q. et al., PNAS, 2021, 35, e2108647118
Subjects
Magnetic Resonance Imaging
Vibrated gas-solid fluidized beds
Numerical Modelling
DDC Class
620: Engineering