Experimental investigations of aeration efficiency in high-head gated circular conduits

Abstract

The primary purpose of water aeration is to increase the oxygen saturation of the water. This can be achieved by using hydraulic structures because of substantial air bubble entrainment at these structures. Closed conduit aeration is a particular instance of this. While there has been a great deal of research on air-demand ratio within closed conduit, very little research has specifically addressed aeration efficiency of closed conduit. In the present work an experimental study was conducted to investigate the aeration efficiency of high-head gated circular conduits. Results showed that high-head gated circular conduits were effective for oxygen transfer. The effects of Froude number and ratio of the water cross-sectional flow area to the conduit cross-sectional area on aeration efficiency were particularly significant, whereas the effect of conduit length was only moderate. Further, a design formula for the aeration efficiency was presented relating the aeration efficiency to ratio of water cross-sectional flow area to conduit cross-sectional area and Froude number. The obtained results will be useful in future modeling processes and aid the practicing engineer in predicting aeration efficiency for design purposes.

Influence of square jets in Oxygen transfer in an Open Channel

“…The impact of the Froude number on oxygen transport was examined by Aydin [26], which is an important metric in hydraulic engineering. The results from this study (as shown in figure 6) are consistent with prior research [27][28][29][30][31] in demonstrating that this dimensionless parameter has a significant influence on oxygen transfer.…”

Experimental investigation of oxygen transfer efficiency in hydraulic jumps, plunging jets, and plunging breaking waves

“…Close similarities in aeration and energy dissipation performances were found between the classical hydraulic and Type B jumps, while Type D jumps showed lower energy dissipation efficiency and aeration (Montano & Felder 2020). Cihat et al (2014) indicated that high- head gated circular conduits flow system might significantly increase the dissolution of oxygen in the water. Data drivenmodels were employed for estimating hydraulic jump oxygen aeration efficiency (E 20 ) under a sluice gate using experimental data and sensitivity analysis and showed that Reynolds number was a significant parameter in the estimation of E 20 (Tiwari 2019).…”

A review: Aeration efficiency of hydraulic structures in diffusing DO in water

“…Cihat Tuna et al. [18] investigated the aeration efficiency of high-head gated circular conduits and discovered that the Froude number and the ratio of water cross-sectional flow area to conduit cross-sectional area had a significant impact on aeration efficiency. The details of conduit aeration including air entrainment rate, performance of conduits etc.…”

“…[43] L=500cm; W=4.5cm; H=9.5cm θ=45°; φ= 5-20mm High pressure and air entrainment at the downstream of conduit facilitated aeration efficiency 5 Cihat Tuna et al. [18] L=2 to 6m θ=45° 2 and 49 Oxygen can be transferred effectively through high head gated circular conduits. The results revealed that when Fr > 20, the increasing tendency of aeration efficiency decreased.…”