Burris Vickie L, McGinnis Daniel F, Little John C
Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg 24061-0246, USA.
Water Res. 2002 Nov;36(18):4605-15. doi: 10.1016/s0043-1354(02)00176-8.
Water flow rate, gas-phase holdup, and dissolved oxygen (DO) profiles are measured in a full-scale airlift aerator as a function of applied air flow rate. A model that predicts oxygen transfer based on discrete-bubble principles is applied. The riser DO profiles are used to calculate the initial bubble size. The range of calculated bubble diameters obtained using the model is 2.3-3.1 mm. The Sauter-mean diameter of bubbles measured in the laboratory ranged from 2.7 to 3.9 mm. The riser and downcomer DO profiles and gas holdups predicted by the model are in close agreement with the experimental results. A model that predicts water flow rate based on an energy balance is used to calculate Kt, the frictional loss coefficient for the air-water separator. Excluding the data at the very lowest air flow rate, the range of calculated values for Kt (3-8) is close to a literature value of 5.5 proposed for hydrodynamically similar external airlift bioreactors. The models should prove useful in the design and optimization of airlift aerators.
在全尺寸气升式曝气器中，测量了水流速、气相持液率和溶解氧（DO）分布随施加空气流速的变化情况。应用了一个基于离散气泡原理预测氧气传递的模型。利用上升管的DO分布来计算初始气泡尺寸。使用该模型得到的计算气泡直径范围为2.3 - 3.1毫米。在实验室中测量的气泡索太尔平均直径范围为2.7至3.9毫米。该模型预测的上升管和下降管的DO分布以及气相持液率与实验结果密切吻合。使用一个基于能量平衡预测水流速的模型来计算气水分离器的摩擦损失系数Kt。排除最低空气流速下的数据，Kt的计算值范围（3 - 8）接近为流体动力学相似的外部气升式生物反应器提出的文献值5.5。这些模型在气升式曝气器的设计和优化中应会证明是有用的。
