No abstract

The concentration of dissolved oxygen is an important indicator of water quality because aquatic life lives on the dissolved oxygen in 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. In the present study, experiments were carried out to investigate the role of cross‐sectional geometry of high‐head gated conduit in oxygen transfer efficiency. In the first part of this study, the role of cross‐sectional geometry of high‐head gated conduit in air‐demand ratio was investigated. In the second part, the role of cross‐sectional geometry of high‐head gated conduit in oxygen transfer efficiency was investigated. Results pointed that the cross‐sectional geometry of the high‐head gated conduit had an important effect on the air‐demand ratio and the oxygen transfer efficiency. Moreover, a design formula was obtained for the conduit having the highest oxygen transfer efficiency relating the oxygen transfer efficiency to air‐demand ratio, Froude number, gate opening, conduit length and gate opening ratio. There was good agreement between the measured and the predicted values. The obtained results will be useful in future modelling processes and aid the practicing engineer in predicting oxygen transfer efficiency of high‐head gated conduits.

Fertigation involves dissolving fertilizer in irrigation water, and requires uniform water distribution and fertilization. A gated conduit can be used to inject liquid fertilizers or chemicals into a pressurized irrigation system. When the conduit gate is partially opened, a vacuum draws the fluid from the suction pipe into the conduit. An experimental study was conducted to investigate the fluid-injection ratio of gated conduits, which shown to be high. The density and viscosity of the fluid were the most important parameters affecting the fluid-injection ratio. That ratio increased with increasing Froude number. It decreased as the gate opening proportion increased and with increasing conduit length. A design formula related to the Froude number, and the fluid's density and viscosity is presented to enable estimation of the fluid-injection ratio.

Gated conduits involve high-velocity air-water flow. When the studies on the gated conduits are examined, it is determined that the air-demand ratio changed according to the hydraulic and geometric parameters. However, no study has investigated the effect of the cross-sectional geometry of high-head conduits with a sluice gate on the air-demand ratio. In this study, the effect of conduit cross-sectional geometry on the air-demand ratio is examined. Results indicate that conduit cross-sectional geometry is an important effect on the air-demand ratio, especially at 10% and 15% gate opening rates. It is seen that the effect of the conduit geometry on the air-demand ratio decreases at 20%, and greater gate opening rates. Moreover, a formula for the air-demand ratio is presented relating the air-demand ratio to the gate opening rate, Froude number, hydraulic radius, and conduit length was presented for estimating the air-demand ratio.

The design flow rate, the dimensions of the transmission structure and the penstock size have a large impact on the cost of run-of-river type hydroelectric power plants. Equipment costs constitute a large part of the total budget of the plant. Optimum sizing, which maximizes the use of hydraulic potential, does not fit together with optimum sizing, which is necessary to obtain economic benefit from its investment. The main design parameters can be selected with the help of an optimization study in terms of both economic benefit and hydraulic potential. In this study, an easy to implement model, aimed at determining the costs associated with the different components in the structural organization of a hydroelectric power plant, is developed by a feasibility study to overcome the difficulties in practice. Gökçeköy HEPP, built in Turkey, was selected as the system. Annual energy production values were calculated by taking into account the current energy market conditions in Turkey. In addition, real situation studies were carried out regarding design flow rate selection, forced pipe diameter optimization and transmission channel sizing.