NUMERICAL AND EXPERIMENTAL STUDY ON TWO-PHASE FLOW IN A SWIRLING FLOW BUBBLE GENERATOR
Micro/nanobubble generation technology has attracted widespread attention in recent years due to its potential in various fields, such as; drinking water and wastewater treatment, agriculture, material technology, medicine and medicine, energy systems and food industry . The hydrodynamic cavitati...
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| Format: | Theses |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/81215 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Micro/nanobubble generation technology has attracted widespread attention in
recent years due to its potential in various fields, such as; drinking water and
wastewater treatment, agriculture, material technology, medicine and medicine,
energy systems and food industry . The hydrodynamic cavitation method using a
swirling flow is a superior micro/nanobubbles generation method compared to
other methods due to its higher efficiency, lower cost, and ability to operate at
various pressures and flow rates. Research and development are being done to
obtain better bubble generator designs.
In this study, experiments and numerical studies were conducted to investigate the
two-phase flow in a swirling flow bubble generator and the dimensional properties
of the generated microbubbles. Computational Fluid Dynamic (CFD) combined
with the Population Balance Method (PBM) was used for the numerical simulation.
The transient solver was used in the simulation with mixture model for the twophase
flow, Turbulent model for the aggregation kernel and Lehr model for the
breakage kernel. The two-phase flow in the swirling chamber and bubble generator
outlet was recorded using a high-speed camera at a varied flow rate ratio (Qw/Qg).
The bubble size distribution obtained was analyzed using the Particle Image
Velocimetry (PIV) method.
Two-phase flow modelling with the CFD-PBM method utilizing the transient solver,
the mixture model, the Turbulent model for aggregation kernel, and the Lehr model
for breakage kernel has been confirmed to yield good predictions of bubble size
distribution and two-phase flow characteristics in the swirling flow bubble
generator. The bubble size distribution obtained from the experimental results
shows an increase in the generated microbubbles by 12-19% when the water flow
rate increases from 20 to 32 L/min. Meanwhile, the change in the oxygen gas flow
rate from 0.5 to 1 L/min did not have a significant effect.
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