Flow Characteristics in the Cross-Section of Spiral Flow Aeration Basin

Abstract

Flow pattern and flow characteristics of spiral flow aeration basin were studied experimentally in the light of the two-region model proposed by the authors.
The size of the bubble-rich region formed by a perforated tube sparjer increased proportionally with air flow rate to the power of 0.3, while that formed by a porous plate diffuser remained constant with respect to air flow rate. The relationship between size of bubble-rich region and setting depth of the air-diffusing unit was approximately linear irrespective of the type of air-diffusing unit.
Although the exchanging liquid flow rate between the two regions was found to be a complicated function of operating and geometrical variables, the flow rate was correlated well by one variable group, i.e., the air flow rate divided by the ratio of bubble volume to mixed volume of bubble-rich region.