Optimal Model Of Stir Energy Distribution For Flocculation And Its Experimental Verification

Flocculation mixing energy distribution is the key problem of a flocculation reasonable design.In recent years,many research achievements have been made on flocculating rationalization design by means of flocculation dynamics theory, but so far the optimal allocation of flocculation stirring energy consumption can only rely on experience, has yet not seen theoretical instructions and related reports. Therefore, this paper combined theoretical model exploration and specialized experiment method to make in-depth study on related subject, undoubtedly having good theory and technology value。In order to reach the new 1 NTU turbidity standard of drinking water quality in China, considering the technical and economic conditions of the majority of water supply plant in the small and medium-sized town, aiming at the influence of the flow pattern on the water treatment effect in the flocculation process and problems existing in the engineering design, This project is supported by the mathematical derivation of existing empirical formula and predecessor's experimental data, the coagulation optimal turbidity range and synergies of the factors influencing flocculants body forming were studied by the beaker experiments. Taking the numerical simulation of the flow pattern within the stirring containers as the main contents, the theoretical analysis and experimental research are combined to explore the best coagulation control conditions, and then develop technical renovation experimental methods for coagulation facilities of waterworks in small and medium-sized town. Flocculation mixing energy consumption assignment problem is the key problem for reasonable design of flocculation tank, but at present the project design can only rely on experience, i. e., adopting design specification experience data, lacking corresponding theoretical support, therefore, this area was discussed as the core of this thesis.The specific content is as follows:(1) The theory optimal models for flocculation energy consumption have been conducted;Thereunto,γis model parameters of flocculants body fractal dimension, mainly relevant to flocculants varieties and dosing quantity. This type expressed numerical scale relation between three gears flocculation stir intensity in the shortest total stirring time. Then we get four ratio calculation formulas for energy distribution optimization of flocculation reaction pool. For the any two, developing flocculation reaction pool water force mixing conditions, design proposal can be achieved at the least whisking time and the most province capacity;(2) The new flocculation condensed set model has been presented to calculate the flocculation body equivalent size (equivalent low moisture content and sedimentation rate); the new flocculent body settlement formula has been derived;(3) Experiments prove themain factors affecting flocculent body fractal dimension is the varieties and coagulants and the dose, without obvious correlation with the water pH value and stir intensity. Experiments have found the size of flocculent body fractal dimension is linear with the dose of coagulant, decreases with dosing quantity; the more the dose, the smaller the size of flocculent body fractal dimension;(4) The optimum operating conditions for flocculation has been got through the multi-factors orthogonal experiments. Experimental results have proved the correctness of the optimal pattern;(5) The numerical simulation of flocculation of hydraulic conditions was made by means of CFD method. The simulation shows it is reasonable to substitute energy dissipation rateεfor flocculation effective energy consumption,the best GT value distribution conforms to theory model proposed by this thesis;(6) The proposed flocculating sedimentation experiment device, flocculent body image processing and fractal dimension calculation methods provides a new means for flocculation technology research in water treatment.Through self-made experiment device, we made real-time dynamic observation and determination of flocculation body .The conclusions are as follows:(1) Energy distribution theory model was put forward and validated by experiments, serving as basic basis for flocculating design;(2) Flocculent collection model was presented, which can undertake moisture content (porosity) calculation, and the new flocculent settlement formulas were derived to make improvements of particles sinking velocity formula in the traditional precipitated theory.