Influence of multiphase microstructure and rheology on the dynamics of bubble growth and release from viscoelastic soft sediments

The growth, retention and release of trapped gas within soft sediments is critically important in many natural and engineered systems; from methane formation within the muddy beds of aquatic reservoirs and wastewater sludges to safety concerns from hydrogen gas release in corroded legacy nuclear wastes. This project will seek to significantly enhance our knowledge of these systems, by examining the mechanisms of bubble growth and release in viscoelastic sediments. In particular, we will focus on characterising the interplay between sediment microstructure (e.g. porosity) and fluid rheology on the dynamics of initial single bubble growth, secondary formation of interconnected bubble networks and the resulting influence on continuous gaseous release. The project will combine state-of-the-art x-ray CT measurements and visual data analysis with Lattice-Boltzmann and Monte Carlo techniques to simulate gas flow through porous networks (e.g. see Figure) as well as analytical modelling to link sediment rheology to bubble growth dynamics. The project is a collaboration with Sellafield, the U.Ks largest nuclear operator, with outcomes transferrable across natural sedimentology, particle engineering and complex fluid sciences.