A Research Of The Design And Structural Optimization Of The New Three-product Hydrocyclone By Numerical Simulation

Hydrocyclone has been widely applied; so many experts and scholars from domestic and overseas have conducted a large number of various aspects of researches. The theoretical basis about the design methods、separation mechanism and application practice has been established perfectly at present. The research about three-product hydrocyclone was posterior to the conventional hydrocyclone and insufficient in the internal flow field、the pressure and the separation mechanism, so, the research about three-product hydrocyclone in this paper has not much relatively good theoretical or practical conclusion to use for reference. The application of three-product hydrocyclone has been gradually realized and has important value in many fields such as papermaking industry and oil industry. Therefore, three-product hydroclone is a very important research direction for its great development potential. Numerical simulation was carried out on structure optimization and separation mechanism of the new type hydroclone in this paper.First, this report simply describes the separation mechanism and introduces the design principles of the structure of new three-product hydrocyclone, chooses the three parameters of the structure optimization, including spigot diameter、middle baffle length and middle baffle diameter.Second, this paper separately analyzed the influence of spigot diameter、middle baffle length and middle baffle diameter on separation efficiency、characteristic parameters、flow field and pressure by the method of numerical simulation. The conclusion is that, spigot diameter and middle baffle diameter have little effect on separation efficiency while middle baffle length has a relatively significant impact on separation efficiency. When the Db=104.54 mm, the separation efficiency was highest. Spigot diameter and middle baffle diameter have a relatively large influence on pressure and tangential velocity while the change of middle baffle length has a small influence on them. Spigot diameter has significant influence on the diversion ratio of water and middle baffle length and middle baffle diameter have an almost ignored influence on it. The analysis of the influence of spigot diameter(Du)、middle baffle length(Lb) and middle baffle diameter(Db) on structure parameters can draw a conclusion that, the optimal structure of the new three-product hydrocyclone is Du=14.00mm、Lb=85.00 mm 、Db=104.54 mm.Third, the result shows that the separation efficiency of the new three-product hydrocyclone is superior to the primary single cylinder hydrocyclone by the analysis comparing these two hydrocyclones. The pressure distribution of these two kinds of hydrocyclone is similar, and the pressure of new three-product hydrocyclone is slightly larger. The distribution of internal flow field of these two hydrocyclones is as well similar, but there are some subtle differences: the trajectories of particles in the new three-product hydrocyclone are more complicated. Within new three-product hydrocyclone, particles enter the cyclone form the outer cyclone, through the downward flow, the larger particles directly discharged from spigot of outer cyclone, other particles enter the upward flow and then enter into the inner cyclone, through the downward flow, most of the middle size particles discharged from spigot of inner cyclone, small particles enter upward flow, and finally discharged from overflow.Finally, this report analyzed the main interaction force and change rule of different size particles in the new three-product hydroclone. The movement of the particles is mainly affected by the fluid drag force、pressure gradient force and the centrifugal force. The fluid drag force、pressure gradient force and the centrifugal force are tend to decrease with the particles size increases, they have a relatively great change when the particles are small, and they remain unchanged when the particles are large.