| The technique of aeration,as the key part of biochemical treatment in the sewage plant, isthe chief section of energy expenditure and spends a large sum of construction funds. So it hasbecome a problem all the countries in the world to develop a wastewater treatment facilities withsimple structure, low energy expenditure and easy management. Jet aerator especially self-suction jet aerator can meet the need well. However, the available common self-suction jetaerator all over the world has no advantage in power efficiency, which prevents its extension.This project develops a new equipment named coreless-cyclic self-suction jet aerator, whichis made by adding a central pipe in the common self-suction jet aerator. This new device has thecharacteristic of internal-external suction,which enlarges the mixing layer, the shear layer of theactuating medium and the extracted air, and increases the contact area of the two fluids,soreinforces the swirling and mixing functions of the actuating medium to the extracted air.This paper investigates the effect of the new device on oxygen transfer performance byorthogonal experiment designs considering the interaction. The results show that:1. The significance order of the three considered constitution parameters to oxygen transferperformance is: nozzle's contracting angle(α) has the greatest influence, throat pipe'slength-diameter ratio(L/D) takes second place and central pipe relative location to nozzle(Lr)doesn't have important influence.2. The optimum combination of the three studied constitution parameters is: α=16°, L/D=10,Lr=100%. The corresponding overall oxygen transfer coefficient(Klas) is 0.051min-1, thetheoretical power efficiency(E) is 2.92KgO2/Kw·h.3. The interaction of L/D with Lr is the most apparent, the interaction of L/D with α is a bitless, and that of Lr with α is by far the least. |
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