The Effects Of Additional Mechanism On Classification Performance Of Hydrocyclone

Aiming at the problems that entrainment of coarse particles in overflow and entrainment of fine particles in underflow, this paper mainly carries out the following three work:firstly, two tests were hydrocyclone classification of different structures and overflow product classification; secondly, a mathematical model was built to describe the classification curve of the hydrocyclone, then the fitting analysis was made on the test data; finally, numerical simulation was carried on of the flow field in conventional hydrocyclone and the hydrocyclone with entity guide ring.The classification performance of conventional hydrocyclone and hydrocyclone with guide ring(entity type and sieve type) was studied in different process parameters, and the contrast test analysis was made among the three structure. The results show that:the structure parameter and operating parameter both influence the classification performance of different structure hydrocyclone, the effect of overflow tube diameter, overflow tube insertion depth and feed pressure are obvious. With adding the entity guide ring, the handing capacity of hydrocyclone is increased, the classification granularity is largen and the classification accuracy is reduced; the fine particle in the underflow is reduced, but it didn’t significantly improve the classification effect. With adding the sieve guide ring, the handing capacity of hydrocyclone is obviously increased, the classification granularity is obviously largen; the granularity less than0.125mm in the underflow is obviously reduced.To add a vortex sieve tube on the overflow of conventional hydrocyclone, is used for classifying and desliming of overflow product. The test results are examined under the condition of different sieve seam form, sleve seam width and export size of plus sieve. With adding the vortex sieve tube, a large amount of fine mud is removed. When the sieve seam is vertical, classification effect is better due to the effect of incision from sieve seam.A mathematical model based on generalized Logistic distribution was established for describing the classification curve of hydrocyclone. Through the fitting of test data, the results show that the mathematical model can well fit the actual classification data. At the same time it can intuitively represent the index which include classification granularity, classification accuracy and fitting error. It is a classification curve mathematical model with well adapted and well-defined parameter.Numerical simulation was carried on of the flow field in conventional hydrocyclone and the hydrocyclone with entity type guide ringv by using CFD. Static pressure, axial velocity, radial velocity, tangential velocity and phase was carried on the contrast analysis at the vertical section and interface of cylinder and cone.As can be seen from the simulation results, the distribution of static pressure, axial velocity, radial velocity and tangential velocity are basically consistent. With adding the entity guide ring, and compared with conventional hydrocyclone, the static pressure is generally smaller within0.03-0.75mm radius, but there is no longer fluctuation within0.01mm radius. Tangential velocity is also smaller, and the decrease amplitude is especially bigger in the center. There is a sharp decrease firstly and then increase wave process of radial velocity in the center. Axial velocity increases sharply in the center, significantly bigger than conventional hydrocyclone.As can be seen from the phase diagram, air-core isn’t entirely formed in conventional hydrocyclone. There is still air-water mixture in the cylinder. Entire air-core forms in the hydrocyclone with entity guide ring, the water phase separates from the air phase.