Simulate And Study On Single-tank Flow Condition And Mixing Power Optimizing Configuration

During the past one hundred years development, sewage biologic treatment has experienced a process of simple to complicate and then back to the simple. Now, the focus in this field has been switched to the development of the simple technique of sewage treatment. Single-tank system is actually the integrative simple technique of sewage treatment based on the above idea. In order to get a idiographic mixing effect of the single-tank, to ensure the activated sludge not to be the sediment in the ditch, it is necessary to own adequate drive power. Otherwise, it will cause many problems such as the awful mixed flow of single-tank, the huge consuming of the energy etc.As a part of the doctoral fund item——optimization theory and engineering research on energy arrangement of multicity sewage treatment, this thesis made a mensuration of the velocity of flow in the main ditch of integerated oxidation ditch which is similar to the single-tank and take rotary disk and submerged propller as the power. Accroding to the measured data, this thesis also made an analysis of the distributing characteristic of the the velocity of flow about the experiment single-tank from three aspects of the single run of the aerate rotary disk, the single run of the submerged propller and the combination of the two instruments.Based on the analysis and measurement, this thesis indicates that the suitable setting place of the aerate rotary disk should be in 15m distance from the curve bend entrance. Thus, the fast velocity of flow upside will averagely spreads to the middle and the bottom, and then into curve bend. The good effect of this is that it can reduce the energy loss caused by the fierce collision at curve bend wall and training wall. Meanwhile, this thesis suggests that the distance between the submerged propller and the lengthways setting place of the curve bend should be close to the 2/3 of the straight part's length. In this way, when the flew reaches the curve bend, it can not only avoid the condition of back mixing caused by the strong drive, but also solve the problem of aggradation caused by the decline of the drive power. Besides, it also illustrates the effects of training wall on the curve bend fluid state and point out a proper setting way of the training wall, affording some theoretical basis and references to the actual project.The thesis uses RNG k–εturbulence model which was ameliorated aimed at eddy flow and curve bend wall flow to make a simulation of the experiment single-tank velocity fiele when the submerged propller run seperatelly. It imports the notion of ideal...