Structural Design And Numerical Simulation Of Fiber Ball Filter

The fiber ball filter, as a depth filter, has a wide range of applicationsfor treatment of wasterwater in oil fields, municipal wastewater andindustrial wasterwater. Meanwhile, with the improvement of thestructures,Some different fiber balls and the fiber ball filters have beendeveloped.In this thesis, structures of the pressent used fiber ball and the fiberballs filters were summarized and their advantages and disadvantageswere analyzed.Problems of the fiber ball filters in applications were alsodiscussed. By analyzing the possible reasons, some solutions are given.Based on the analysis, a new structure of the fiber ball filter was proposedand all the drawings about the filter are completed.In the thesis, the backwash process of the fiber ball filter wassimulated with the software FLUENT. Surge phenomenon was found andthe cause was analyzed. Based on the analysis, a new structure of fiberball filter was proposed. Numerical simulation indicated that with theproposed new structure, the surge phenomenon in the backwash processcan be avoided and thus the filting efficiency can be improved. Also in this thesis, the porous media model in FLUENT was firstly applied tosimulate the pressure drop of the fiber ball filter in use.The results werecompared with experimental measurements. It is found that both resultsare very close, indicating that numerical simulation with FLUENT for thepressure drop in the fiber ball filter is applicable and creditable.Finally, numerical analysis was also performed for the effects of thepermeable compression plate on the filting process. Flow fielddistribution in the filter bed corresponding to different heights of thepermeable compression plate is obtained. It is found that the height of theplate does affect the filting process. Therefore in engineering application,the height of the premeable compression plate should be optimized inorder to have a high filting efficiency.