Cyclone Optimization And Inner Short Circuit Flow Research Based On Numerical Simulation

As a type of gas-solid separation device using centrifugal force,Cyclone separator has been widely used in the chemical,mine and other industries due to the characteristics of simple structure and feasibility to maintain.The research of the mechanism of gas-solid separation has also attracted much attention in the field of Helicopter inlet and air cleaner.Both the experimental method and numerical simulation are the main methods in the study of cyclone separator.A reliable result can be achieved by the experimental method with high expense and a long cycle.With the rapidly development of CFD,not only the advantages in expense and cycle,but also the ability to simulate the complex flow pattern inside the cyclone separator,that make the numerical simulation method plays an indispensable role in the study.The performance of cyclone separator can be improved directly by means of optimizing the structural and operational parameters and the change of parameters essentially affects the internal flow pattern.Therefore,the study of the internal flow mechanism has the advantages of theoretical significance.In this paper,the collection efficiency and pressure drop as the cyclone separator two key performance indicators,the work done is as follows:The first is to optimize the structural parameters of the cyclone separator.The RSM and random walk method model were applied to investigate the performance difference among the cylinder shape?contracted-shape and reversed-contracted shape.The main purpose is to obtain the change rule between collection efficiency and pressure drop as the vortex finder diameter and shape changes.The second is the joint optimization of structural parameter and operational parameter.The COMPLEX algorithm was introduced to optimize the variance of structure and inlet velocity.The optimized model improve 7.56%collection efficiency and lower 29.99%pressure drop by 61.01%inlet velocity compared with the original model.The most important factor affecting the separation efficiency of the cyclone is due to the "short circuit flow" phenomenon at the end of the vortex finder.Part of the dust stream flows directly into the upper swirling flow along the end of the vortex finder,without sufficient separation trajectory processes.Therefore,the "short circuit flow" phenomenon is a mechanism problem in the study of cyclone separator.In this paper,a new method of "short circuit flow" is proposed,and the Box-Behnken experimental design is used to establish the "short circuit flow" prediction model equation.The results show that the predicted value agrees well with the simulated value.