Numerical Simulation And Optimization Research Of New Sedimentation Device

As an important structure in the water treatment, the clarifier has a very wide rangeof applications. But traditional clarifiers has many defects such as large occupation ofland, high quantity of sludge reflux, great consumption of flocculants and lowutilization ratio. In order to overcome these defects, two clarifiers have been developed,which are pump suction sludge external reflux clarifier and pipe/tube sludge internalreflux clarifier. Both of them take the spiral inclined plate as the technical essentials,and the experimental results show that: they have strong ability to resist impact load,effluent quality is stable and good, and flocculants consumption is little.In view of the good sludge separation effect of the spiral inclined plate, the thirdclarifier has been developed. Setting zone of the first two clarifiers is anisotropic flow,and the third is co-directional flow. Based on the analysis of the basic theory of thesedimentation process and research status at home and abroad, and the research,development and operating experience of the spiral inclined plate, a new spiral inclinedplate sedimentation process is proposed, which is the co-directional flow and sidewater-out. The design and optimization of traditional equipment is based on thepractical experiment, establishment of an experimental model or field testing. It ischecked and optimized by changing the experimental conditions and parameters, and itlack of theoretical basis. Although the results are more reliable, but it also take lot oftime to do the experiment, and it is costly, there is too many subjective and objectiveinfluencing factors. In order to avoid these disadvantages, the software Fluent is used tosimulate the new spiral inclined plate sedimentation device with solid-liquid andtwo-phase flow model at first. The removal rate of suspended solids is studied, and thenexperiment are proceeded to examine the actual effect of sedimentation and verify thecorrectness of the simulation results, so it will provide some useful reference for thedesign and operation management of the clarifier.The simulation of the new spiral inclined plate sedimentation device can point outthe way to optimize it. According to the sludge concentration distribution situation ofthe spiral plate area, the arrangement position of outlet has a greater effect on theeffluent concentration; According to the flow rate of the spiral plate area, the mountingangle of the spiral plate is also a factor; Reference to the inclined plate sedimentationtank of co-directional flow, the bezel can be setted on the upper part of the small holes to change the direction of the sludge and to improve the removal rate. So changing thethree structural parameters and conducting some simulations can get the best method foroptimizing.The different factors such as suspended particle density, particle size, the sludgevolume fraction and inlet velocity and different working conditions take effect on thesediment, to study the effect, the numerical simulation of optimized spiral inclined plateclarifiers is operated. Sedimentation efficiency of the spiral plate can be obtained formthe sludge volume fraction of outlet and the removal of suspended solid, and thesimulation results show that it has a very good removal rate.In order to test the the the spiral inclined plate sedimentation device and verify thesimulation results, the experimental study is conducted. The experimental results have agood agreement with the simulation results, and it has a high removal rate.