Project
Computational fluid dynamics study of granular flows
Despite the many advantages of microchemical systems, their increased surface-to-volume ratio leads to difficulties in the handling of solid laden flows. This is especially problematic when solid particles are formed as a by-product of a chemical reaction. In these cases, the amount of solid by-product gradually increases along the axial extent of the microreactor, eventually leading to clogging of the microreactor channels. Specifically, bridging and constriction have been identified in earlier studies as candidate mechanisms for clogging. Being able to manage solid-laden flows in a continuous matter is an important step in the batch to continuous transition.
In this project we will model flow systems containing fluids and particles in micro-scale geometries using a coupled discrete element method (DEM) / computational fluid dynamics (CFD) approach. In this method, the DEM part is used to solve the equation of motion for each particle, and the continuous fluid is described by solving the Navier-Stokes equations using CFD tools. Specifically, this project focuses on the implementation of particle-wall and particle-particle interactions for the prediction of particle deposition on the wall (constriction) and particle agglomeration in the bulk of the fluid (bridging), and thus to predict microchannel clogging. The numerical work will be done using the open-source code OpenFOAM, which allows the implementation of new solvers and models, and thus represents a solid framework for code development.
The obtained results will allow for the fundamental description and quantification of bridging and constriction events in solid-laden flows in microchannels and will provide guidelines for clogging prevention and design of flow reactors. One major outcome will be to relate the channel and particle surface properties to the clogging risk and operation time of micro-scale devices.