Empirical Modeling of Oxygen Uptake of Flow Over Stepped Chutes
The present investigation evaluates the influence of three different step chute geometry when skimming flow was allowed over them with the aim of determining the aerated flow length which is a significant factor when developing empirical equations for estimating aeration efficiency of flow. Overall, forty experiments were conducted in the Hydraulics Laboratory of the Department of Water Resources and Environmental Engineering, Ahmadu Bello University Zaria-Nigeria to determined the aeration efficiency of flow over the three different chute geometry at the water temperature T and at the standard temperature of 200C. Data of the aeration parameters were analysed using a regression model to develop an empirical equation used for the prediction of aeration efficiency of flow for the three chute geometry under consideration. The results revealed that the aeration efficiency increases with an increased in the length of aeration but decreases with an increased in both the critical depth and roughness Froude number. The results also indicated that percentage of the length of aeration range from 51.6-71.4% over the stepped chute length for the range of unit discharge of 43.4-26.1 L/s.m. The aerated length in all the three chute geometry showed that they could contribute significantly to the overall aeration efficiency, especially the inclined chute type. The inclined chute configuration could be employed, optimally, as a water treatment structure.