Numerical Simulation And Experimental Research Of Hydrocyclone With Sieve Overflow Pipe

The phenomenon of overflow roughness in the traditional hydrocyclone is caused by coarse and fine particles that have not been completely separated,or directly enter the overflow pipe without separation.To solve the above problems,this paper proposes a sieve overflow pipe,by closing the bottom of the overflow pipe and setting a mesh,reduces the carrying amount of coarse particles in the overflow,and adjusts the distribution of the flow field inside the hydro cyclone by changing the structure of the overflow pipe to obtain improved tangential speed,increase the optimized structure of the separation area,etc.,thereby improving the classification efficiency.In this paper,through the combination of numerical simulation and laboratory tests,the separation performance of the sieve overflow pipe hydrocyclone was studied in depth.The research results have certain guiding significance for improving the fine separation of the hydrocyclone.In this paper,FLUENT is used to numerically simulate the proposed sieve and ordinary overflow pipe hydrocyclone,and the internal flow field distribution and separation performance are explored.The simulation results show that:compared with the ordinary circular overflow pipe hydrocyclone,the internal pressure of the screen type overflow pipe hydrocyclone is higher,the tangential velocity is large,the axial velocity is small,the separation ability is strong and the flow field is stable,The separation is sufficient,the content of fine particles in the overflow is relatively large,and the classification performance is better than that of the ordinary hydrocyclone.The reason for its better separation performance is that the sieve overflow pipe changes the internal flow field and enters the overflow pipe The coarser particles in the sieve are effectively screened out,so that they can participate in the separation again and be discharged through the underflow.Secondly,the influence of the feeding pressure,the opening ratio of the overflow pipe,the size and diameter of the opening and the diameter of the underflow opening on the Φ50mm sieve overflow pipe hydrocyclone were studied,and laboratory experiments were carried out,Using the product concentration,underflow yield,throughput,flow distribution ratio and hydrocyclone classification performance as indicators to analyze the separation performance of the sieve overflow pipe hydrocyclone,the results show that within a certain pressure range,the pressure increases can provide a stronger centrifugal force field for the hydrocyclone separation process,so that the overall classification efficiency increases and the separation particle size decreases;as the opening rate of the overflow pipe increases,the hydrocyclone processing capacity increases and the overall classification efficiency increases;overflow The size of the opening of the overflow pipe is increased,and the separation particle size of the hydrocyclone is increased.The test found that a fine overflow product can be obtained when the opening diameter is 1.5mm;the diameter of the overflow tube has a significant effect on the yield of underflow,and the separation particle size increases with the diameter The flow distribution ratio increases obviously with the increase of the diameter of the underflow port.When the diameter of the underflow port is 8 mm,the comprehensive classification efficiency of the sieve overflow pipe hydrocyclone reaches the highest.Finally,the three-level orthogonal test of four factors,namely feeding pressure,overflow pipe opening size,overflow pipe opening ratio and overflow pipe diameter,was designed to explore the optimal combination parameters of the sieve overflow pipe hydrocyclone.The optimal hydrocyclone working parameters under the indicators of overflow yield and comprehensive classification efficiency.Taking the overflow yield as the evaluation index,the optimal combination parameters of the sieve overflow pipe hydrocyclone are:feeding pressure 0.08MPa,overflow pipe opening size 2mm,overflow pipe opening rate 43%,overflow The pipe diameter is 24mm.Taking comprehensive classification efficiency as the evaluation index,the optimal combination parameters are:feed pressure 0.10 MPa,overflow pipe opening size 1.5mm,overflow pipe opening ratio 43%,overflow pipe diameter 24mm.In summary,by studying the separation performance and influencing factors of the sieve overflow pipe hydrocyclone,an optimized structure for obtaining high classification efficiency and reducing coarse particles in the overflow is obtained,and the classification accuracy and comprehensive classification efficiency are improved for the traditional hydrocyclone It has certain theoretical significance and practical value.