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: 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.
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ABSTRACT: RESUMO Na confecção deste trabalho se utilizou a metodologia de superfície de resposta para otimizar o efeito do número de Reynolds, tempo de floculação e concentração de hipoclorito de sódio sobre a oxidação/floculação do ferro presente em águas subterrâneas em um sistema de aeração com autoaspiração de ar. O sistema se compunha de um vaso tipo Ventu-ri, acoplado a um tubo de mistura para promover a oxigenação da água através da sucção do ar atmosférico. O mapea-mento hidrodinâmico permitiu verificar as condições de operação no qual o sistema apresentou melhor eficiência de sucção de ar e menor consumo de energia, além de compará-las com as melhores condições a campo. Os resultados observados demonstraram que foi possível a remoção de 98,7% do ferro presente (residual ferro de 0,06 mg L -1) quando o sistema operou com número de Reynolds no estrangulamento do Venturi de 5,39 x 10 4 , concentrações de hipoclorito de sódio de 38,4 mg L -1 e tempo de floculação 30 min. A metodologia de superfície de resposta foi satisfatória e permi-tiu otimizar as variáveis operacionais citadas. Palavras-chave: aeração, águas subterrâneas, metodologia de superfície de resposta, remoção de ferro Optimization of auto-aspiration aeration system type Venturi for the treatment of ferruginous water ABSTRACT In this study the response surface methodology was used to optimize the effect of Reynolds number, flocculation time and sodium hypochlorite concentration on the iron oxidation/flocculation present in groundwaters in an aeration system with air auto-aspiration. This system was composed of a recipient type Venturi coupled to a mixture tube to promote the oxygenation of the water through the suction of the atmospheric air. The hydrodynamic mapping allowed the verification of the operation conditions in which the system presented the best air suction efficiency and energy consumption, and the comparison of the best field conditions. The observed results demonstrated that it was possible to remove 98.7% of present iron (residual iron of 0.06 mg L -1) when the system operated with Reynolds number of 5.39 x 10 4 , sodium hypochlorite concentrations of 38.4 mg L -1 and flocculation time of 30 min. The response surface methodology was satisfactory and allowed for the optimization of the mentioned operational variables.01/2010;
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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