Die Filling of Aerated Powders

Publication Reference: 
Author Last Name: 
Chuan-Yu (Charley) Wu
Report Type: 
Research Area: 
Powder Flow
Publication Year: 
Publication Month: 
United Kingdom

Executive Summary Various shaped dies have been used to manufacturing particulate products of distinctive shapes in a number of industries (e.g. pharmaceutical, agrichemcials, ceramics). Although the formulations and manufacturing systems used are similar, the powder behavior during die filling could be affected by the orientations of dies when nonaxisymetric dies are used. However, there is little understanding of the effect of system set-up on die filling behavior. Therefore, a systematic study on the effect of the shape and orientation of dies on powder flow behavior was performed numerically. Using the inhouse DEM-CFD code, a methodology was developed to model complex die geometries, for which triangular meshes were employed to discretized the complex boundaries. Using the developed methodology, various die shapes, including circle, square, ellipse and rectangle., were modeled and the effect of orientation for non-axisymetric dies on die filling were explored and presented in Section 1. It is found that the dies with larger aspect ratio and parallel orientation (to the filling direction) lead to smaller mass flow rates and lower critical velocities. In addition, the dies with elliptic openings can generally give higher critical velocities than those with rectangular shapes. These results indicate that for die filling with non-axisymetric dies the system set up, especially the orientation, can have a significant impact on the powder flow behavior during die filling. An experimental apparatus was also developed and some preliminary study using this mode die filling system was performed and reported in Section 2. Further improvement of the measurement robustness is on-going. It is hence planned that, in the 2nd year of this project, the following tasks will be performed (details are given in Section 3): • Experimental study of the effect of system design on die filling of aerated powders (Task 2c of the IFPRI proposal). • Experimental study on segregation during die filling with mixtures of aerated powders (Task 2b of the IFPRI proposal). • DEM-CFD analysis of segregation during die filling with aerated powders (Task 1b of the IFPRI proposal).