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Quantitative 'real-time' imaging of multi-phase flow in ceramic monoliths
A J Sederman1, M D Mantle, L F Gladden
1Department of Chemical Engineering, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, UK. ajs40@cheng.cam.ac.uk
Magnetic Resonance Imaging
|July 10, 2003
Summary
A new imaging technique visualizes real-time gas flow in liquids using multiple images from one radio-frequency excitation. This method quantifies gas bubble dynamics in ceramic monoliths, revealing flow rate and channel size effects.
Area of Science:
- Magnetic Resonance Imaging
- Fluid Dynamics
- Materials Science
Background:
- Understanding two-phase flow in porous media is crucial for industrial processes.
- Ceramic monoliths are used in various applications requiring fluid flow management.
- Real-time imaging of gas-liquid interactions in such structures presents significant challenges.
Purpose of the Study:
- To develop and validate an advanced magnetic resonance imaging (MRI) technique for real-time visualization of gas flow.
- To quantify gas-phase volume fractions, bubble size, and velocity distributions.
- To investigate the impact of varying gas flow rates and ceramic channel sizes on gas bubble dynamics.
Main Methods:
- An extended RARE (Rapid Acquisition with Relaxation Enhancement) pulse sequence was developed to acquire multiple images from a single radio-frequency excitation.
- The technique was applied to image gas flow through stagnant liquid within parallel-channel ceramic monoliths.
- Image analysis was performed to extract quantitative data on gas bubble characteristics.
Main Results:
- Real-time imaging successfully captured gas flow dynamics within ceramic monoliths.
- Gas-phase volume fractions, bubble length, and velocity distributions were directly obtained.
- Increased gas flow rates led to larger bubbles and higher average bubble velocities.
- A bimodal bubble velocity distribution was observed in 300 channels per square inch (cpsi) monoliths, versus a unimodal distribution in 400 cpsi monoliths.
Conclusions:
- The developed MRI technique provides direct, quantitative insights into gas-liquid two-phase flow in ceramic structures.
- Channel size significantly influences gas bubble velocity distributions, with larger channels promoting bimodal flow characteristics.
- This imaging approach offers a powerful tool for optimizing designs involving gas flow in porous materials.