Researcher: Wei Pin Goh
Principal Investigator: Professor Mojtaba Ghadiri
Co-Investigator(s): Professor Frans Muller
Industrial Supervisors: Dr Nandkishor K. Nere & Dr Raimundo Ho
Sponsor: AbbVie Inc.
Status: Ongoing (2015-current)





University of Leeds


This project addresses thermal and mechanical stress-induced transformation (e.g. polymorphic and solvate/desolvation) in manufacturing of organic particulate solids and provides a methodology for assessing and quantifying the extent of such phase transformations. The project focuses on the transformations, which takes place from formed crystal to final product during the process engineering operations. The aim of this project is to develop a predictive capability for determining the occurrence of various form changes and particle attrition during the agitated drying process. Changes in particle size and shape and the creation of imperfections are also be investigated. This requires characterisation of the initial material, along with the material that has been exposed to agitated drying under a range of operating conditions. The specific objectives are as follows:
To characterise the physical and mechanical properties of model crystals at the single particle level: size, shape, polymorphic form, harness, stiffness and toughness of the initial materials.
To quantify stresses arising in the agitated bed in the presence of liquid and at drying temperatures.
To characterise bulk mechanical properties of the resulting particles.
To predict the onset of size, shape and phase changes, along with the nature of the exposed faces of the particles as a result of the stresses caused by the agitated drying.
To characterise particle breakage at the bulk level in simple devices, such as an annular shear cell.
To relate the bulk breakage to single particle properties using modelling.

 (Double-click on the video to go full screen)

Simulation of an agitated particle bed of rounded cylinders using ROCKY DEM.


Goh, W.P., Ghadiri, M., Muller, F., Sinha, K., Nere, N., Ho, R., Bordawekar, S & Sheikh, A. (2017). Stress analysis of an agitated particle bed with different particle aspect ratios by the discrete element method. EPJ Web Conf. doi:10.1051/epjconf/201714006022