On the Use of Venturi Tubes in Aeration
ABSTRACT The ecological quality of water depends largely on the amount of oxygen that the water can hold. The higher the level of dissolved oxygen, the better the quality of a water system. By measuring dissolved oxygen, scientists determine the quality of water and health of an ecosystem. Oxygen enters water by entrainment of air bubbles. Many industrial and environmental processes involve the aeration of a liquid by such entrainment of air bubbles. Venturi aeration is a method of aeration that has become popular in recent years. When a minimal amount of differential pressure exists between the inlet and outlet sides of a venturi tube, a vacuum (air suction) occurs at the suction holes of the venturi tube. The present paper describes the effect of Reynolds Number, air inlet hole diameter, inlet diameter, pipe length, and angle of pipe downstream of the venturi tube, on the air injection rate. It is observed from the results that venturi tubes have high air injection efficiencies. Therefore, venturi tubes can be used as highly effective aerators in ponds, lakes, fish hatcheries, water treatment plants, etc.
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ABSTRACT: The oxygen concentration in water is a prime indicator of the water quality for human use as well as for the aquatic biota. The physical process of oxygen transfer or oxygen absorption from the atmosphere acts to replenish the used oxygen. This process is termed re-aeration or aeration. Venturi aeration is a method of aeration that has become popular in recent years. A venturi tube allows air bubbles to be inserted into flowing water from air inlet holes and so increases oxygen levels in the water. In the present study, a series of experiments on venturi tubes were conducted to investigate the effect of air inlet hole diameter on air injection. It was observed from the results that air inlet hole diameter on venturi tube played a significant role in air injection and there was an optimal diameter that maximizes air injection. Moreover, a multiple non-linear regression equation was obtained for venturi tubes relating air flow and water flow to Reynolds number, inlet diameter and air inlet hole diameter. Keywordsaeration-air injection-venturi-water qualityKSCE Journal of Civil Engineering 01/2010; 14(4):489-492. · 0.38 Impact Factor
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ABSTRACT: The effect of aerator module configuration, liquid flow rate and diffuser submergence on oxygen transfer efficiency was examined in a surface aeration system with venturi injectors using the clean water test. Six venturi aerator modules were evaluated and the results indicated that better aeration efficiencies could be achieved by simply changing the way the venturi aerators were connected. Among all the configurations examined (modules a-f), two and three aerators connected in parallel (modules d, e and f) were able to bring more oxygen into water than the others. An increase in liquid flow rate led to an enhancement of the oxygen transfer coefficients, but the improvement was reduced if the liquid flow rate was too high. The oxygen transfer coefficient was found to have a relationship with the depth of diffusing pipes (surface aeration depth) for the surface aeration system and an optimal depth of around 40 cm was obtained from this study.Environmental Technology 06/2012; 33(10-12):1289-98. · 1.61 Impact Factor
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ABSTRACT: As the water passes through a restriction in a pipe, it forms a vacuum at the end of the restriction. A hole bored into the pipe at a point where this vacuum occurs will cause air to be drawn into the main flow. One example of this mechanism is seen in the venturi tube. When a minimal amount of differential pressure exists between the inlet and outlet sides of the venturi tube, a vacuum occurs at suction holes of the venturi tube. Venturi aeration is a method of aeration that has become popular in recent years. In present paper, air injection rates of venturi tubes are analyzed using Computational Fluid Dynamics modeling. These analyses are carried out by means of the program FLUENT V6.2 that uses finite volume theory. There is a good agreement between the measured air injection rates and the values computed from FLUENT CFD program.© Association for Scientific Research. 01/2009; 14:97-108.