Zhekai Deng

Continuum modeling of segregation for polydisperse granular materials in hopper discharge flow

Zhekai Denga,d, Yi Fand, Jörg Theuerkaufd, Karl V. Jacobd, Paul B. Umbanhowarb, Julio M. Ottinoa,b,c, Richard M. Lueptowa,b,c
a Department of Chemical and Biological Engineering, Northwestern University, IL 60208, USA
b Department of Mechanical Engineering, Northwestern University, IL 60208, USA
c The Northwestern University Institute on Complex Systems (NICO), Northwestern University, Evanston, IL 60208, USA
d The Dow Chemical Company, Midland, MI 48667, USA

Predicting polydisperse segregation during hopper discharge is useful for applications in bulk solids handling across many industries. However, because of the relative complexity of the flow kinematics during hopper discharge and the limited research on polydisperse segregation, little progress has been made in modelling polydisperse segregation in hopper flow. A continuum approach based on a modified transport equation that captures advection, diffusion, and segregation effects in the flow is developed to model the material transport and polydisperse segregation in the hopper flow. Combined with a hopper filling model, which provides the initial condition for the hopper discharge process, the model can quantitatively predict polydisperse segregation during hopper discharge. Experimentally validated Discrete Element Method (DEM) simulations are used to validate the hopper discharge model. Quantitative agreement of continuum model predictions with DEM simulation results over a range of hopper geometries, particle size distributions, and flow conditions confirms the modeling approach. The model has the potential to accurately predict hopper discharge segregation at industrial scale and, thereby, enhance hopper design to minimize segregation.


Zhekai Deng
Ph.D. Candidate, Dept of Chemical and Biological Engineering, Northwestern University
Zhekai Deng is currently finishing a PhD in Chemical and Biological Engineering at Northwestern University, working with Richard Lueptow, Paul Umbanhowar, and Julio Ottino. Zhekai’s research focuses on predicative models for mixing and segregation of particle flows. He uses both computational and experimental tools to quantify the behavior of dense flowing particles and develops theoretical models to describe the phenomena observed in the computer simulations and experiments. Zhekai received his B.S. from the University of Rochester in Chemical Engineering and Applied Mathematics. He will begin a position at The Dow Chemical Company soon.