Basic Research On Flow Field Simulation And Computational Theory Of Falcon Concentrator

As the gorwing rate of fine coal washing and the limitation of high sulphur in market, it has been impendency issues for current coal industry that looking for more effective technology to desulfurization and deash fine coal. However, Falcon concentrator did have an advantage of which uses centrifugal field to classify mineral. In this paper, mainly base on computational fluid dynamics, flow field characteristics of Falcon concentrator was studied.To make sure of the accuracy,high speed dynamic camera was used to observe the flow field and prove the computational results were accurate.This paper summarized the development of fine coal on mineral processing equipment and numerical theory of multiphase flow including turbulence model and drag models.The developments of CFD and observing tests on multiphase flow was also summed up.The computational theory of Falcon was organized and improved.Thickness of flow film formulas both in stratification and retention zones, recoilwater flow rate formula and limit of separation formula were built with a series of proving tests. Studies have shown that flow film in stratification zone is in proportional to inlet speed but inverse proportional to rotate speed,howover flow film in retention zone is in proportional to recoilwater pressure;flow rate is relate to pressure and opening structure;limit separation of Falcon is got from highest pulse height of particales and surface waves.To know more about the flow field of Falcon, high speed dynamic technology tests were carried on.Accroding to theimage analysis, we found that flow film distribution isdovetail with computational analysis and the formulas are quite accurate.Reynolds stress model was also prove to be well for simulation of Falcon.In addition, atomization was found in flow field, which caused backflow.From the simulation in which Eulerian model as multiphase model and RSM as turbulence model,we got particales movement in diffrient zones,distributions of velocity in three vectors and the distribution of turbulence field.By the researches mentioned,we found that particales pathlines are dimensional helical with a certain flow around;velocity in stratification zone is similar to other centrifuge concentrators, but in retention zone is totally diffierent; a significant turbulence was caused by recoilwater, which keep in a thin film at the bottom of retention zone.Furthermore, simulations above were applied to deal with practical issues, such as priciples of Falcon concentrator,structural improvement and so on.