Research On Separation Performance Of Sludge Dewatering Decenter Centrifuge

A solid precipitation in the sewage purification process effluent matter is left, which is called sludge. The pool sedimentation is commonly used in sewage treatment plants, which gets the sludge’s watery percentage up to about97percentage, then the Centrifuge is used for the solid-liquid separation. The sludge fluid movement in the helical flow path of the spiral centrifuge is extremely complex solid-liquid two-phase swirling flow, and it is taken the numerical simulation combined with experimental validation to study the separation performance. The specific work is as follows.First, the sludge fluid physical model for the solid-liquid separation of the helical flow path in the Centrifuge has been built; within fluent of the CFD simulation software, the mathematical model of the solid-liquid two-phase flow in the Centrifuge helical flow path has been built,which provided the conditions for the solid-liquid two-phase flow numerical simulation.Second, application of the above physical geometry and mathematical models, velocity, pressure and turbulent kinetic energy in the Centrifuge internal solid-liquid two-phase flow field have simulated and got the velocity, the pressure field and the turbulence distribution, analysed the relationship between the flow field and the separation performance.Third, using the RNG k-∨turbulence model and MRF model,the sludge fluid in the Centrifuge helical flow path within the different structural parameters by numerical simulation to study the influence of the structural parameters on the performance of the solid-liquid separation, got the drum length to diameter ratio, drum half-cone angle and import the angle of incidence of the Centrifuge for the solid-liquid separation performance.The fourth, the sludge in the Centrifuge flow field has simulated under the different operating parameters, got the relationship between the differential rotational speed of the conveyor and drum of the Centrifuge and the separation performance, and found the optimal rotational speed of the Centrifuge, but also the maximum processing capacity of the sludge characteristics of the Centrifuge, and the sludge handling capacity of the Centrifuge under the different sludge’s watery percentage.The fifth, the separation performance of the Centrifuge within the differential speed and different treatment experiments, the result shows that the maximum error between the experimental data and numerical simulation results in less than9percentage. This research results can guide the design and use of the Centrifuge. KEY WORDS:centrifuge, two-phase flow, numerical simulation, separation performance...