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

在许多自然和工程系统中，软沉积物中捕获气体的生长、保留和释放至关重要；从水生水库和废水污泥泥床中的甲烷形成，到腐蚀遗留核废料中氢气释放的安全问题。该项目将通过研究粘弹性沉积物中气泡生长和释放的机制，大大提高我们对这些系统的认识。特别是，我们将重点描述沉积物微观结构（例如孔隙率）和流体流变学之间的相互作用，这些相互作用涉及初始单个气泡生长、相互连接的气泡网络的二次形成以及由此产生的对连续气体释放的影响。该项目将结合最先进的x射线CT测量和可视化数据分析，结合格点-玻尔兹曼和蒙特卡罗技术，模拟气体通过多孔网络的流动（如见图），以及分析模型，将沉积物流变学与气泡生长动力学联系起来。该项目是与英国最大的核运营商Sellafield合作的，其成果可在自然沉积学、颗粒工程和复杂流体科学领域进行转移。

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.