Prediction of Aeration Performance for Inverted Umbrella Aerator Based on Dimensional Analysis

Abstract

As core equipment of the wastewater treatment process in chemical enterprises, the inverted umbrella aerator has been well studied in the areas of structural design and performance improvement. However, the relations between two devices which are geometrically and dynamically similar are far from having been thoroughly researched. This paper aims at investigating the relationships between geometrically and dynamically similar aerators and establishing a general performance prediction model for them. Based on dimensional analysis, the effect of structure on aeration performance is formulated by dimensionless relational expressions using the experimental data of reduced-scale aerators (reduced-scale model), and thus the performance prediction mathematical model for other aerators with geometrical and dynamical similarities is established. The Froude number Fr is found to be the most important affecting parameter of the improved absorption number Y, which is the only dimensionless number characterizing aeration performance. Validation of the formulas is conducted through the comparison of predicted values and experimental data in two validation aerators whose scale differences to reduced-scale model are 33% and 66%, respectively. Finally, the maximum average relative error between predicted values and experimental data was 8.92%, which indicates that the formulas are reliable and applicable to the performance prediction of the scaled aerator through the data of its reduced-scale prototype.