Abstract
Sintering - or coalescence - of viscous droplets is an essential process in many natural and industrial scenarios. Current physical models of the dynamics of sintering are limited by the lack of an explicit account of the evolution of microstructural geometry. Here, we use high-speed time-resolved x-ray tomography to image the evolving geometry of a sintering system of viscous droplets, and use lattice Boltzmann simulations of creeping fluid flow through the reconstructed pore space to determine its permeability. We identify and characterize a topological inversion, from spherical droplets in a continuous interstitial gas, to isolated bubbles in a continuous liquid. We find that the topological inversion is associated with a transition in permeability-porosity behavior, from Stokes permeability at high porosity, to percolation theory at low porosity. We use these findings to construct a unified physical description that reconciles previously incompatible models for the evolution of porosity and permeability during sintering.
Original language | English |
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Article number | 033113 |
Number of pages | 6 |
Journal | Physical Review E |
Volume | 96 |
Issue number | 3 |
DOIs | |
Publication status | Published - 25 Sept 2017 |
Externally published | Yes |
Funding
Processed data and raw 3D datasets are available from the corresponding author on request. Funding was provided by the European Research Council Advanced Grant No. 247076 (EVOKES) and Starting Grant No. 306488 (SLiM), and UK NERC Grants No. NE/N002954/1 and No. NE/M018687/1. We acknowledge the Paul Scherrer Institut for provision of beam time under Proposals No. 20141231 and No. 20150413, the four referees for helpful comments, and Jenny Schauroth for sample material preparation.
Keywords
- X-ray tomography
- fluid dynamics
- drop interactions