Permeability of polydisperse magma foam
Permeability of polydisperse magma foam
复制标题
多分散岩浆泡沫的渗透率
DOI：
10.1130/g47094.1
复制
发表时间：
2020
期刊：
影响因子：
5.8
通讯作者：
Donald Bruce Dingwell
中科院分区：
文献类型：
--
作者：
J. Vasseur;F. Wadsworth;Donald Bruce Dingwell
有效的岩浆渗透性演化模型是理解浅部岩浆上升和喷发动力学的关键。模型通常是经验性的构造，通常集中在单分散系统，并且无法科普高孔隙率下的泡沫极限。在这里，我们确认，在高孔隙度火山碎屑中的气泡尺寸分布是高度多分散的。我们联合收割机整理的实验数据和数值模拟，以测试和验证各向同性岩浆渗透率的理论基础渗流模型，该模型考虑了气泡尺寸的多分散性的影响。我们发现，多分散性控制的逾渗阈值。它还可以作为渗透率缩放的重要输入，这是实现渗透率描述的普遍性所需的。我们的模型对高孔隙度火山岩的渗透率整理公布的数据表现良好。然后，我们扩展这个模型来预测流体流动的粘性和惯性的贡献，需要在所有制度的岩浆放气模型。我们的比例关系在整个范围内的孔隙度，从渗流阈值开放泡沫限制。
Effective models for the evolution of magma permeability are key to understanding shallow magma ascent and eruption dynamics. Models are generally empirical constructs, commonly focused on monodisperse systems, and unable to cope with the foam limit at high porosity. Here, we confirm that bubble size distributions in high-porosity pyroclasts are highly polydisperse. We combine collated experimental data and numerical simulations to test and validate a theoretically grounded percolation model for isotropic magma permeability, which accounts for the effect of polydispersivity of bubble sizes. We find that the polydispersivity controls the percolation threshold. It also serves as essential input into the scaling of permeability that is required to achieve universality in the description of permeability. Our model performs well against collated published data for the permeability of high-porosity volcanic rocks. We then extend this model to predict the viscous and inertial contributions to fluid flow that are required to model magma outgassing in all regimes. Our scaling relationship holds across the full range of porosity, from the percolation threshold to the open-foam limit.