Research Of Filtration Processing With Vibratory Shear Flow And Enhancement Performance

How to solve the problem of filtration flux decreases sharply with time that cause by filtering media contamination and cake layer thickening is an important research field in Solid-Liquid separation area. The traditional filtration enhancement method is increasing the shear of the surface of filtering media though improving the inlet velocity or adding a rotational disk. But that limited in application because of the high energy consumption and complex structure and difficulty sealing. Vibratory-Shear-Enhanced-Processing produces shear stress with the disk torsionally oscillating. It just limited by distance and frequency of oscillation, could solve the problem mentioned above efficaciously. So it has a widely applied foreground in the engineering area.A set of experimental system of Vibratory-Shear-Enhanced-Processing filtration separator is built in this study and a series of experiments and model research are conducted.As to experimental research, the influence of operation parameters such as concentration of suspension, displacement and frequency of oscillation are discussed on the filtration flux. And the other parameters such as the type of different grain and diameter of the same grain are also researched. The results of experiments show that with the increase of concentration, filtration flux decreases sharply and static filtration flux also decreases, the increase of displacement and frequency of oscillation can enhance static filtration flux and reduce the contamination of filtering media. For different type of grain, if it forms the compressible cake layer, the filtration flux would be higher. For the same grain, the smaller the diameter is the higher the filtration flux we got. The results verify that filtration separator with Vibratory Shear Enhanced Processing has a greater filtration performance compared with traditional filtration separator with cross-flow.In theoretical model area, the paper gains the distribution of velocity and shear stress for both disk oscillating though analyzing N-S equation and continuity equation. The max of shear vibratory shear stress enhanced flow is 70-90 times bigger than conventional cross-flow though the calculation.As to experimental model analysis, two mathematical models of filtration flux were built. An empirical equation for static filtration flux and an empirical equation for dynamic filtration flux are presented and verified by experimental data respectively. In the former, influence factors are summed up into the displacement and frequency of oscillation and some important dimensionless numbers like Re_g and Eu to obtain a feasible formula that provides basis for scale-up of the module. The latter which based on the previous study considering the influence of concentration of suspension, displacement and frequency, describes the real variation of filtration flux with time and provides evidence for real-time monitoring of the filtration process.The results of above study demonstrate that Vibratory-Shear-Enhanced-Processing has great enhancement performance and the filtration separator with it has great practical engineering value for its remarkable advantages such as high shear rate, simple structure, convenient operation, low energy consumption and easy to industrial scale-up.