Machine design for auger dosing of powders by utilizing DEM simulations and multivariate-regression-based experimental analysis
El Kassem, Bilal; Markert, Bernd (Thesis advisor); Eberhard, Peter (Thesis advisor)
Aachen : RWTH Aachen University (2021)
Dissertation / PhD Thesis
In: Report. IAM, Institute of General Mechanics IAM-08
Page(s)/Article-Nr.: 1 Online-Ressource : Illustrationen, Diagramme
The aim of the underlying work is to develop a statistical methodology that identifies the correlations between critical material attributes, critical process parameters and critical quality attributes of a volumetric vertical micro-auger dosing process and to end up with building a loss in weight (LiW) feeder. In this, shear cell analysis and other various empirical tests are used to characterize 30 material attributes of ten different powders ranging between free-flowing and cohesive ones that are widely used in the drug industry. The analysis is done using principal component analysis, which reveals the (dis)similarities between the powders and identifies overarching attributes. Thereafter, regression analysis is applied to find possible correlations between the studied factors. Moreover, as a numerical approach, Discrete Element Method (DEM) simulations are performed to model the granular material flow in an auger dosing process. Two main studies are carried out to calibrate and validate the studied powders with the experimental reference values. The successful application of the multivariate regression analysis results in predicting the bulk behavior of the powder by clustering different predicted behaviors of various responses together which allows to dramatically reduce the admissible parameter combinations. Consequently, an optimized set of calibrated DEM parameters is chosen, where the simulation results accurately match with the experimental data. The essential goal of this contribution is to present the alternative vertical LiW feeder dosing concept. In a systematic design process, based on functional design specifications, the semi-automated vertical LiW feeder for dosing a wide range of powders, especially cohesive ones, is developed. Experimental sensitivity analysis and powder dosing tests to study the functionality of the machine and to investigate the weight variability of a weighing platform is successfully accomplished. As a result, the proof of concept prototype is validated.