Swirl Bubbles Effects on Hydrodynamic Characteristics of an Air-Water Bubble Column
Gas liquid bubbly flow reactors are used in chemical, petrochemical and bioprocess industries to enhance the mass transfer between the gas and liquid phases. The two-phase bubble column has gained huge attention for few decades due to its complex hydrodynamics and its impact on transport characte...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2020
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| Subjects: | |
| Online Access: | http://ir.unimas.my/id/eprint/31439/1/Ariny%20Anak%20Demong%20ft.pdf |
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| Summary: | Gas liquid bubbly flow reactors are used in chemical, petrochemical and bioprocess
industries to enhance the mass transfer between the gas and liquid phases. The two-phase
bubble column has gained huge attention for few decades due to its complex
hydrodynamics and its impact on transport characteristics. The gas is dispersed to create a
small bubble and disseminate them consistently to maximize the intensity of mass transfer.
The motion of bubble’s rise in liquids is fascinating due to the bubble’s ability of adopting
a variety of bubble’s motion patterns, which are characterized on the basis of bubble’s
wakes, instability and size & velocity. This thesis describes bubble’s swirl effects on
hydrodynamic characteristics in an air-water bubbly flow. The experimental set up
comprises a cylindrical column, with a ring-cone sparger. The measurement technique
contains a digital high-speed camera and image analysis software to track multiple moving
bubbles. Bubble’s size, population and radial migration distance have been identified from
consecutive pictures as a result of bubble’s edge recognition and projection on the basis of
edge recognition for each of the bubble. The results from the experimental works show that
by increasing the sparger rotation speed from 30 rpm up to 150 rpm, bubbles size is
reduced, but bubble population is increased. Hence, the bubble migration distance is higher
when the sparger’s rotating speed increases. Increasing gas flowrate results in larger
bubble size, while promoting rotation induced by the sparger decreases the bubble size. As
the rotating speed increase, the radial velocity of the water also increases. This is because,
at high rotating speed, the velocity is dispersed more to the surrounding. Thus, at the center
of the column, the liquid velocity is higher due to the bubble rising velocity is greater. As a
conclusion, swirling bubble can enhance the mixing between air and water as well as
provide larger migration of bubbles in the air water system. From this study, the efficiencyiv
of the air-water mixing is increased, thus gives knowledge that by inducing swirl bubble in
the flow, we can enhance the performance of the bubbly flow process. |
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