CFD-Based Structural Optimization of Rotor Cage for High-Efficiency Rotor Classifier

Xinliang Mou,Ying Fang,Chuanwen Chen,Fangchao Jia

doi:10.3390/pr9071148

Abstract

Due to the uneven materials dispersion and high dust concentration in industrial applications of turbo air classifiers, a high-efficiency rotor classifier was designed. Numerical simulations by ANSYS-Fluent 19.0, the effects of rotor cage shape, the number of blades, and the blade profile on the inner flow field, as well as classification performance, were investigated. The simulation results indicated a significant improvement in flow field distribution near the classification surface with the conical rotor cage. Furthermore, there was an average reduction of 10.1% in cut size, as well as a 23.6% increase in classification accuracy. When the number of blades was 36, the flow field distribution between the blades was relatively uniform and a smaller cut size was obtained at a higher classification accuracy. A streamline blade with 52° as the inlet installation angle effectively reduced the impact of the airflow on the blade and eliminated the inertia anti-vortex between blades. The cut size reduction was 4.7–6.3%, with a basically unchanged classification accuracy. The material classification experimental results were in agreement with the simulated results. The discrete phase model (DPM) could well-predict the cut sizes and classification accuracy, but it could not present the fishhook effect. The present study provides theoretical guidance for the structural optimization of an air classifier with a rotor cage.

Highlights

An air classifier is a key piece of equipment in the powder preparation process that is widely used in the mineral processing, food processing, and fine chemical industries [1,2,3,4]
With the surge in demand for powder production capacity, many problems have arisen in the industrial application of turbo air classifiers due to structural limitations [5,6]
On issue is a high dust concentration in the annular area; material classification is mainly concentrated in the annular area, so if a material cannot be sorted out in time, this would be a high dust concentration in the annular area, which would increase the chance of particle collision and reduce classification accuracy

Summary

Introduction

An air classifier is a key piece of equipment in the powder preparation process that is widely used in the mineral processing, food processing, and fine chemical industries [1,2,3,4]. The performance requirements for air classifiers are increasing with applications of ultra-fine powders. The turbo air classifier is a mainstream dynamic classifier for industrial applications that has a simple structure and controllable product granularity. With the surge in demand for powder production capacity, many problems have arisen in the industrial application of turbo air classifiers due to structural limitations [5,6]. The materials in the annular area mainly rely on the impact guide blade to settle and be collected as coarse powder. With 2 of impact guide blade to settle and be collected as coarse powder. The guide vanes wear o as a result and cannot be replaced due to structural limitations. Wi the rapid development of computational fluid (CFD), dynamics (CFD), researchers have focuse the rapid development of computational fluid dynamics researchers have focused more attention on the study of powder classification technology and the development more attention on the study of powder classification technology and the development classification equipment, and theymade have progress made progress in many respects

Methods

Results

Conclusion