摘要：Water quality and its enhancement have a close connection with the presence of dissolved oxygen concentration. In fact, the dissolved oxygen concentration in waters is a prime indicator of the water quality. Aeration is the process that absorption of oxygen from atmosphere to water. Many hydraulic structures are used for aeration. Hydraulic structures increase the amount of dissolved oxygen significantly, even though the water is in contact with the structure for only a short time. Venturi and gated conduits are hydraulic structures that has become popular in recent years. Venturi has throat portion and air hole located into throat portion. A pressure difference is occured between inlet and throat portion of venturi. This pressure difference is the reason of aeration in venturi. In a gated conduit when the gate partly opened pressure difference occured between upstream and downstream of the gate. Air entrains into flow from an air vent that were drilled downstream of the gate. In this study a new aeration system is called venturi-conduit was used for aeration. A venturi was placed on air hole of a circular conduit. Two air hole was drilled on the throat portion of venturi. A series of experiment was conducted for investigation the aeration performance of venturi-conduit for three case of venturi. Aeration performance was investigated primarily only main air hole, then main hole and one air hole and then main hole and two air holes. In the venturies Dt/D=0.75 and Dt/D=0.90 increasing the length of conduit is not an important effect on air entrainment rate QA/Qw in all P values. P=%20 has the highest air entrainment rate QA/Qw in both. It is observed that the air hole case of venturi is not a significant effect on air entrainment rate QA/Qw. The results obtained from the experimental methods were procured by using regression analysis method. Analysis results were examined and successful results were obtained. Air entrainment rate (QAir/QWater) can be calculated with the equations for Dt/D=0.75 and Dt/D= 0.90.
