ER 1

DEM-CFD multiphase modelling of fines agglomeration and dispersion

The main goal of this project is to investigate, by means of numerical simulation, the process of clustering of colloidal suspensions (i.e. solid particles suspended in a liquid or gas). If the solid particles have a size range of 10-6 to 10-9m, they can be characterized by low Reynolds and Stokes numbers. The potential applications are enormous and can impact different fields such as water treatment and purification, the food industry, oil and gas, microfluidics and environmental processes, blood flow, and even the explanation of the origin of life on earth. The numerical methodology envisaged will be a hybrid between the Discrete Element Method (DEM), Brownian Dynamics (BD), and in the later stages, Stokesian Dynamics (SD). The aim of combining DEM with BD or SD is to account for the contact forces during the collision of the particles (DEM), and also the complex hydrodynamic interactions between the particles and ambient fluid (BD, SD) . In the model considered, several interaction particle forces need to be taken into consideration, for example van der Waals and electrostatic interactions. The main software platform that I will use will be EDEM™ provided by DEM Solutions, which is a DEM solver. The implementation of BD and SD into EDEM will be done using Applications Programmer Interface (API) code. The benefit of combing DEM with either BD and SD is that the theoretical model proposed is not dependent on any empirical correlations such as drag laws, and also is very suitable for simulating dense suspensions.

The effect of the particle size, shape, volume fraction, and pH on the size shape of the agglomerates will be investigated, using supplementary method such asfractal dimension. determination. The verification of the results obtained from the model it will be validated against the available results in the literature from numerical investigations and experimental studies. Upscaling will be accomplished by using a combination of Population Balance Method (PBM) and Computational Fluid Dynamics (CFD), with cluster size and transport properties such as viscosity and mass diffusivity of the particles supplied by the hybrid DEM-BD-SD method.

The originality of the current research project lies in two aspects. The first is on the numerical side, in the combination of DEM, BD, and SD. The second aspect is the investigation of the effect of polydispersity (different particle sizes) on cluster formation, transport and rheological properties of the colloidal suspensions. Currently, the theory behind the BD method is being clarified prior to implementation in the EDEM™ API.

Yousef M. F. El Hasadi


I started my research career in 2000 as a Masters at the University of Benghazi in Libya.

I developed a solver for simulating the flow in circular-sector ducts. This enabled me to publish two journal articles and seven conference papers as first author.

After I had received a very prestigious Fulbright scholarship in the Summer of 2008, I joined Auburn University as Ph.D. student; there I worked on continuum modelling of the solidification of colloidal suspensions.

The models that I used qualitatively predicted the unstable morphology of the solid-liquid interface similar experimental results, the first time such a prediction had been made.

After I had finished My Ph.D. in the summer of 2013, I worked as a Postdoctoral researcher for the same group at Auburn University for one year, investigating the utilization of colloidal suspensions as phase-change materials. At my time at Auburn University I published four Journal and five conference papers.

Yousef M. F. El Hasadi