Computational study on microscale behavior of bubble generated by aeration in a plug-flow aeration tank
Huanran Wang1, Yanpeng Li, Zhixin Zhao
1School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China. huanran@mail.xjtu.edu.cn
Summary
Liquid cross-flow in aeration tanks significantly impacts bubble generation, reducing bubble size and generation time for improved wastewater treatment. This study explores microscale hydrodynamics for enhanced oxygen transfer efficiency.
Area of Science:
- Environmental Engineering
- Fluid Dynamics
- Wastewater Treatment
Background:
- Microscale hydrodynamics of bubbles are critical for oxygen transfer efficiency in activated sludge wastewater treatment.
- Understanding bubble generation phenomena in plug-flow aeration tanks is essential for process optimization.
Purpose of the Study:
- To investigate the effects of liquid cross-flow on the microscale behavior of bubble generation in plug-flow aeration tanks.
- To provide insights into bubble dynamics influencing oxygen transfer efficiency in wastewater treatment.
Main Methods:
- Developed a three-dimensional direct simulation method.
- Employed the level set method coupled with variable property fluid equations.
- Solved governing equations using the finite-volume technique and validated with experimental data.
Main Results:
- Liquid cross-flow significantly alters bubble generation, causing bubbles to grow along a tilted axis.
- Bubble generation time decreases, and detached bubble size is smaller under cross-flow conditions compared to quiescent conditions.
- Increased gas velocity leads to larger bubble size and longer generation time.
Conclusions:
- Liquid cross-flow is a key factor influencing bubble dynamics and oxygen transfer in aeration tanks.
- The findings offer a deeper understanding of microscale bubble phenomena for optimizing wastewater treatment processes.
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