Spreading of granular pastes: from the particle to end use properties
July, 2022: Oral presentation of the project results by Ghita Marouazi, PhD student at LEMTA, during the international conference CHoPS.
June, 2022: Discussion of the results that will be presented during the international conference CHoPS.
March, 2022: Discussion of the results in video, next meeting scheduled for April, 2022.
February, 2022: Discussion of the results in video, next meeting scheduled for March, 2022.
November, 2021: Discussion of the results in video, next meeting scheduled for January, 2022.
June 2, 2021 - Current status: experimental and numerical spreading.
January 26, 2021 - Current status: CFD/DEM simulations and experimental spreading.
October 23, 2020 - Current status: particles properties and confined rheology.
May 4, 2020: Kickoff meeting.
Objectives and research hypothesis
Granular pastes as highly concentrated particle suspensions, such as clay and gypsum pastes and fresh concretes, play an important role in the manufacturing of different products in the construction, chemical, pharmaceutical and food industries. These materials are non-Newtonian fluids whose complex rheological properties (yield stress, thixotropic) need to be understood and described with physical based models to optimize the end-use properties of these products in connection with their formulation. One way to optimize the flow behavior of the pastes is to apply mechanical vibration for targeted control of their viscosity and their spreading behavior. At rest, these materials exhibit a yield stress and present a solid like behavior. Applied mechanical vibrations induced a fluid like behavior which can make them to spread. In this cooperation project, we will combine for the first time original experimental and numerical tools to investigate and describe the flow behavior of granular pastes under influence of vibration.
The main goal of this project is to understand the influence of well-controlled mechanical vibrations on the spreading and the rheology of granular pastes. To this end, we will study how vibrations modify the porosity and the grains dynamics during flow of various kinds of granular pastes and its role on the rheology. Our work will mainly be based on the fact that controlling the energy injected by external vibrations allows controlling of the porosity that is the free volume available for the granular paste to rearrange at the macroscopic scale, so that it enables us to control its viscosity. In this way, we want to characterize vibrated flows of granular pastes with the aim of optimizing their transport and storage properties.
This objective should be realized by the adequate modelling of the rheology of the granular paste on the basis of rheological tests, particle-based microstructural experimental as well as simulation-based investigations. The main focus is on the development of microscale based models, which are able to predict the influence of the disperse phase (particle size distribution, packing structure and concentration, and the adhesive interactions) on the complex flow behaviour of granular pastes by applying vibration. For the description of these microprocesses, the granular paste should be simulated with the coupled Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD).
This PRCI project is an opportunity to combine the expertises of our two teams to conduct an original research on this topic and obtain significant results which could not be obtain without this collaboration.
LBM-DEM simulation of the single particle settling in water with different grid resolutions (property of University of Kaiserslautern)