Promoting Pellet Feed Flow in a Screw Feeder with an Agitator

• Published in: Industrial & engineering chemistry research 2023-04, Vol.62 (15), p.6273-6284
• Main Authors: Huang, Tianci, Qian, Huaiyuan, Li, Zhuo, Zuo, Tianlin, Wu, Bei
• Format: Article
• Language: English
• Subjects: Thermodynamics, Transport, and Fluid Mechanics
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.3c00042

The active agitator is preferred because it enhances the screw feeder’s particle flow characteristics more effectively. Utilizing the discrete element method, a discrete element model of pellet feed was constructed to investigate the impact of the agitator on the discharge performance of the screw feeder. As the focus of the investigation, the screw feeder (consisting of a wedge-shaped hopper and a screw conveyor) was studied. By designing a pair of symmetrical agitators in the wedge-shaped hopper, the effects of different directions (forward slewing, reverse slewing, and isotropic slewing) and different speeds of the agitator on the discharge rate, flow pattern, particle velocity, particle trajectory, and particle interaction force of the screw feeder were studied. Findings indicated that the agitator caused a transition from a funnel flow to a mass flow in the hopper, resulting in more particle movement. The increase in the interaction force between particles in the area above the screw conveyor forced more particles to be squeezed into the screw conveyor. The maximum average discharge rate of 27.89 g/s was achieved when the direction of the agitator was FS, which was 10.38% higher than that without the agitator. There was little to no difference in the discharge rate regardless of the agitator’s direction and speed. In addition, as the discharge progressed, the particle bed height in the hopper decreased, and the promoting effect of the agitator progressively weakened. The discharge rate of the screw feeder showed a trend of first stabilizing and then decreasing, and the interaction force between particles also showed the same trend of change. As shown from the aforementioned studies, the discharge performance of the feeder can be greatly enhanced by installing an agitator. The research findings shed light on how the screw feeder’s agitator works to boost its discharge performance, laying the groundwork for additional improvements to its design.