Numerical Investigation And Performance Optimization Of Elliptical Vibrating Screen

Vibrating screen is a kind of screening apparatus and extensively adopted in particle separation work.In accordance with the vibration trace,vibrating screen can be classified into three typical types: linear vibrating screen,elliptical vibrating screen and circular vibrating screen.Researchers believed that the sieving performance of elliptical vibrating screen is rather outstanding on account of it integrates the merits of linear vibrating screen and circular vibrating screen.Nevertheless,most of current researches were established on a specific vibration mode due to the limitations such as experimental condition,hence it is unreasonable and ineffective to analyze and compare the sieving results of three vibration modes based on different works.Meanwhile,It can be found that the published researches on elliptical vibrating screen mainly concentrated on the theoretical investigation,which probably give rise to some deviation from practice seeing that the vibration screening is a random process.Screening efficiency and processing capacity are traditionally considered as two critical indexes for the evaluation of sieving performance.Nevertheless,Most of optimization studies mainly focus on the improvement of screening efficiency,but neglect the importance of processing capacity.Meanwhile,the interplay between the two indexes also brings many difficulties to the performance optimization of vibrating screen.In this research,linear vibration and circular vibration were regarded as two special forms of elliptical vibration.Aiming at the aforementioned problems and shortcomings,the sieving performance of elliptical vibrating screen was systematically investigated,and the main research contents are as follows:(1)Based on the fundamental principle of Discrete Element Method,the sieving process of vibrating screen was numerically simulated,the motion characteristics and penetration behaviors of feeding materials were analyzed comprehensively.On the basis of simulation results,by extracting the force data of particles which acted on screen surface during the stable screening period,the stress and deformation of screen deck were further analyzed based on the computation of DEM-FEM coupling approach.(2)By adjusting the length ratio between the semi-major axis and the semi-minor axis of elliptical trace,various vibration traces of screen deck were realized.Under the identical screening model and parameters,the influencing rules of vibration trace on different screening indexes were systematically analyzed.(3)Length of semi-major axis,Length ratio of two semi-axes,vibration frequency,vibration direction angle,inclination angle,and vibration direction of screen deck were selected as six crucial parameters for the investigation of elliptical vibrating screen.According to single factor experiments,the influencing rule of each parameter with various values was demonstrated.Furthermore,Taguchi orthogonal experiments were designed for revealing the sequence of those parameters which evaluated by the influence degree.(4)According to the screening results data of elliptical vibrating screen,the prediction models of sieving results were established based on the Gradient Boosting Decision Trees algorithm,and the high prediction accuracy was realized after the optimization on the hyperparameters of model.(5)Based on the prediction models of screening efficiency and screening time,the modified Ant Colony Optimization algorithm was proposed in research for optimizing the sieving performance of elliptical vibrating screen,and the reliability of optimization results were verified by numerical simulation experiments.