Determination of diffuser bubble size in computational fluid dynamics models to predict oxygen transfer in spiral roll aeration tanks
Determination of diffuser bubble size in computational fluid dynamics models to predict oxygen transfer in spiral roll aeration tanks
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DOI：
10.1016/j.jwpe.2016.07.001
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发表时间：
2016-08
影响因子：
7
通讯作者：
Mitsuharu Terashima;M. So;R. Goel;H. Yasui
中科院分区：
文献类型：
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作者：
Mitsuharu Terashima;M. So;R. Goel;H. Yasui
曝气池是污水生物处理和回用系统中去除废水中有机污染物的重要工艺之一。曝气池是污水处理系统中耗能最高的单元之一，利用计算流体动力学(CFD)方法对曝气池的氧气传递进行预测，对于降低曝气池的能耗至关重要。气泡尺寸是CFD模拟中的一个关键参数，对不同类型的扩散器进行了研究。对不同曝气池内的水力进行了CFD计算，并将体积氧传质系数的计算值与实测值进行了比较。模拟了19个不同扩散器类型和曝气强度的净水池和8个污水池。使用CFD模拟中指定的校准dB值来拟合为这些构型确定的KLav值。计算结果表明，粗气泡扩散器、小孔扩散器和狭缝膜扩散器的气泡尺寸分别为7~8 mm、5~6 mm和约3 mm。此外，还进行了CFD模拟，模拟了扩散器结构改变时的流态，并计算了相应的KLavue。
The aeration tank is one of the most important processes in the biological wastewater treatment and water reuse system to remove organic pollutants in wastewater. The prediction of oxygen transfer using the computational fluid dynamics (CFD) method is crucial for minimizing the energy consumption of the aeration tank, which is one of the highest energy consuming units in a wastewater treatment system. Bubble size (dB), which is a critical parameter in the CFD simulations, was investigated for different types of diffusers. CFD calculations were conducted to simulate the hydraulics in different aeration tanks and the calculated values of the volumetric oxygen mass transfer coefficient (KLa) were compared with experimentally measured data. A total of 19 tanks containing clean water and 8 tanks containing wastewater with different diffuser types and aeration intensities were simulated. TheKLavalues determined for these configurations were fitted using a calibrateddBvalue specified in the CFD simulations. The results of the calculations indicate that the coarse-bubble diffusers, fine-pore diffusers, and slitted membrane diffusers have bubble sizes of 7–8 mm, 5–6 mm, and approximately 3 mm, respectively. Additionally, CFD simulations were conducted to simulate the flow pattern and calculate the correspondingKLavalue when the diffuser configuration was changed.