Effect of the rotor cage chassis on inner flow field of a turbo air classifier

2021 ◽  
Vol 52 (7) ◽  
pp. 772-780
Author(s):  
Y. Yu ◽  
X. Kong ◽  
C. Ren ◽  
J. Liu ◽  
J. Liu
Keyword(s):  
Flow Field ◽  
Air Classifier ◽  
Rotor Cage

scholarly journals Numerical Simulation of a Flow Field in a Turbo Air Classifier and Optimization of the Process Parameters

Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 237 ◽  
Author(s):  
Yun Zeng ◽  
Si Zhang ◽  
Yang Zhou ◽  
Meiqiu Li
Keyword(s):  
Flow Field ◽  
Process Parameters ◽  
Production Efficiency ◽  
Rapid Development ◽  
Engineering Application ◽  
Production Equipment ◽  
Powder Materials ◽  
Optimal Process ◽  
Air Classifier ◽  
Rotor Cage

Due to the rapid development of powder technology around the world, powder materials are being widely used in various fields, including metallurgy, the chemical industry, and petroleum. The turbo air classifier, as a powder production equipment, is one of the most important mechanical facilities in the industry today. In order to investigate the production efficiency of ultrafine powder and improve the classification performance in a turbo air classifier, two process parameters were optimized by analyzing the influence of the rotor cage speed and air velocity on the flow field. Numerical simulations using the ANSYS-Fluent Software, as well as material classification experiments, were implemented to verify the optimal process parameters. The simulation results provide many optimal process parameters. Several sets of the optimal process parameters were selected, and the product particle size distribution was used as the inspection index to conduct a material grading experiment. The experimental results demonstrate that the process parameters of the turbo air classifier with better classification efficiency for the products of barite and iron-ore powder were an 1800 rpm rotor cage speed and 8 m/s air inlet velocity. This research study provides theoretical guidance and engineering application value for air classifiers.

Flow Field Characteristic Analyses of a Turbo Air Classifier’s Rotor Cage and its Structurally Improved Counterpart

2008 ◽  
Vol 58 ◽  
pp. 59-67 ◽  
Author(s):  
Qing Liang Yang ◽  
Jia Xiang Liu ◽  
Yun Bo Zhou
Keyword(s):  
Flow Field ◽  
Air Flow ◽  
Flow Behaviour ◽  
Laser Doppler Velocimeter ◽  
Inlet Velocity ◽  
Flow Field Simulation ◽  
Field Simulation ◽  
Air Classifier ◽  
Rotor Cage ◽  
Rotary Speed

The turbo air classifier is one of the most widely used equipment in powder classification. The complex flow behaviour inside it, however, prevents material experiments from providing information about its internal separation mechanisms. A study of the interaction of structural variables is therefore undertaken examining air flow behaviour, specifically the air flow between the blades of the rotor cage. The investigation of these flow field characteristics made use of the computational fluid dynamics (CFD) to simulate the air flow in the classifier. It was found that the inlet velocity of the turbo air classifier and the rotary speed of the rotor cage are two of the dominating, non-structural factors that affect velocity distributions in the region between the rotor cage blades. Once the inlet velocity settles, a critical rotary speed must be present to smoothen the flow field between the blades, resulting in an excellent classification performance. Three-dimensional velocity measurements of the region between the blades by laser Doppler velocimeter (LDV) were performed to test the results of the flow field simulation. This revealed that when inlet velocity is invariable, the velocity distributions in the region between the blades are at its most symmetric with the critical rotary speed of the rotor cage making it more favourable for classification. The velocity measurement results are likewise in good agreement with the results of the flow field simulation. Newly structured rotor cages are also simulated and compared with a conventional turbo air classifier, air flow in the newly structured model is smoother. The distributions of radial and tangential velocities are more symmetric and the trend of the rotating vortex between the blades attenuates, particularly when the rotary speed is high. The newly structured rotor cages can therefore achieve higher classification performances.

Effects of fine particle outlet on performance and flow field of a centrifugal air classifier

2017 ◽  
Vol 117 ◽  
pp. 139-148 ◽  
Author(s):  
Zhanpeng Sun ◽  
Guogang Sun ◽  
Xiaonan Yang ◽  
Yi Yuan ◽  
Qinglian Wang ◽  
...  
Keyword(s):  
Flow Field ◽  
Fine Particle ◽  
Air Classifier

scholarly journals A New Rotor-Type Dynamic Classifier: Structural Optimization and Industrial Applications

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1033
Author(s):  
Fangchao Jia ◽  
Xinliang Mou ◽  
Ying Fang ◽  
Chuanwen Chen
Keyword(s):  
Flow Field ◽  
Radial Velocity ◽  
Tangential Velocity ◽  
Operating Conditions ◽  
Bottom Surface ◽  
Cone Type ◽  
Surface Diameter ◽  
Rotor Cage ◽  
Rotor Type ◽  
Classification Efficiency

Due to the inadequate pre-dispersion and high dust concentration in the grading zone of the turbo air classifier, a new rotor-type dynamic classifier with air and material entering from the bottom was designed. The effect of the rotor cage structure and diversion cone size on the flow field and classification performance of the laboratory-scale classifier was comparatively analyzed by numerical simulation using ANSYS-Fluent. The grinding process performance with an industrial classifier was also tested on-site. The results revealed that an inverted cone-type rotor cage is more suitable for the under-feed classifier. When the rotor cage’s top-surface diameter to bottom-surface diameter ratio was too large or too small, the radial velocity and tangential velocity at the outer surface of the rotor cage greatly fluctuated. Furthermore, the diameter of the diversion cone also affected the axial velocity and radial velocity of the flow field. Models T-C(1-0.8) and T-D(1-0.7) were determined as the best rotor cage structures. Under stable operating conditions, the classification efficiency of the industrial classifier was 87% and the sharpness of separation was 0.58, which meet the industrial requirements for classification efficiency and energy consumption. This present study provides theoretical guidance and engineering application value for air classifiers.

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

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1148
Author(s):  
Xinliang Mou ◽  
Fangchao Jia ◽  
Ying Fang ◽  
Chuanwen Chen
Keyword(s):  
Flow Field ◽  
Structural Optimization ◽  
Field Distribution ◽  
Classification Accuracy ◽  
High Efficiency ◽  
Industrial Applications ◽  
Classification Performance ◽  
Discrete Phase Model ◽  
Rotor Cage ◽  
The Impact

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.

Numerical Study of Classification of Ultrafine Particles in a Gas-Solid Field of Elbow-Jet Classifier

2005 ◽  
Author(s):  
Shibin Liang
Keyword(s):  
Flow Field ◽  
Ultrafine Particles ◽  
High Speed ◽  
Numerical Study ◽  
Experimental Results ◽  
Speed Flow ◽  
Fluent Software ◽  
Air Classifier ◽  
Different Diameters

Computational fluid dynamics (CFD) is applied to develop a novel submicron air classifier. Based on different inner structure sizes and positions in the elbow-jet classifier, the two-dimensional air flow field has been simulated by the Fluent software. The Coanda-effect plays a paramount role in the separation of ultrafine particles in the high-speed flow field of the elbow-jet classifier. The effects on the features of the Coanda element, i.e. a half-cylinder, have been analyzed and discussed. The trajectories of moving particles with different diameters in the channels and chambers of the classifier have been calculated under the velocity field simulation results obtained by the CFD analysis. The cut sizes of three products at the related outlets of the classifier are obtained based on the trajectories calculation of the particles and compared with the corresponding experimental results. The ground/classified experiment has been conducted by using the products outlet of a vortex jet mill as the particles feed of the elbow-jet classifier. The experimental results show that the external classifier for the vortex jet mill improves the classification of the mill significantly. The combination of the vortex jet mill with the external classifier provides a new choice of the grinding equipment for the multiple size products of fine/medium/coarse powders. A centrifugal channel has been added between the vortex jet mill and the elbow-jet classifier to improve the performance of the air classifier. Both numerical and experimental results show that the pre-distributed feed powders at the exit of the centrifugal channel have a strong effect on the fine powders separation and a less effect on the coarse powders separation.

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