Three-dimensional temporal imaging of X-ray CT imaging of dissolution-driven convection in glass beads

Dataset title Three-dimensional temporal imaging of X-ray CT imaging of dissolution-driven convection in glass beads
Dataset creators Dr Ronny Pini, Imperial College London
Rebecca Liyanage, Imperial College London
Qatar Carbonates and Carbon Storage Research Centre
Dataset theme Geoscientific Information
Dataset abstract

The images in this dataset show the mixing of two liquid solutions in a random bead pack as a function of time and in three-dimensions. The working fluids used in this study are solutions of methanol and ethylene-glycol (MEG, fluid 1) and brine (fluid 2). In particular, three mixtures of ethylene-glycol and methanol were prepared that differ in wt% ethylene-glycol, namely 55 wt% (MEG55), 57 wt% (MEG57) and 59 wt% (MEG59). Measurements are conducted using in the regime of Rayleigh numbers, Ra = 2000-5000. X-ray Computed Tomography is applied to image the spatial and temporal evolution of the solute plume non -invasively. The tomograms are used to compute macroscopic quantities including the rate of dissolution and horizontally averaged concentration profiles, and enable the visualisation of the ow patterns that arise upon mixing at a spatial resolution of about (2x2x2) mm3. We observe that the mixing process evolves systematically through three stages, starting from pure diffusion, followed by convection-dominated and shutdown. A modified diffusion equation is applied to model the convective process with an onset time of convection that compares favourably with literature data and an effective diffusion coefficient that is almost two orders of magnitude larger than the molecular diffusivity of the solute. The comparison of the experimental observations of convective mixing against their numerical counterparts of the purely diffusive scenario enables the estimation of a non-dimensional convective mass flux in terms of the Sherwood number, Sh = 0.025Ra. We observe that the latter scales linearly with Ra, in agreement with observations from both experimental and numerical studies on thermal convection over the same Ra regime.

Dataset content dates 18th July 2016 - 9th February 2017
Dataset spatial coverage Not Applicable
Dataset supply format DCM
Dataset language English-United Kingdom
Dataset discovery metadata record Discovery Link to the dataset's BGS Discovery Metadata record
Dataset publisher British Geological Survey
Dataset publication date 21st September 2018
Dataset digital object identifier(DOI) 10.5285/f18a68bf-470f-48b7-91a1-9ea412fca419
Dataset citation text Imperial College London, Qatar Carbonates And Carbon Storage Research Centre (2018): Three-dimensional temporal imaging of X-ray CT imaging of dissolution-driven convection in glass beads. British Geological Survey. (dataset). http://dx.doi.org/10.5285/f18a68bf-470f-48b7-91a1-9ea412fca419
Constraints and terms of use This data set is delivered under the terms of the Open Government Licence, subject to the following acknowledgement accompanying any reproduced materials: "Imperial College London gratefully acknowledge permission to publish and funding from the Qatar Carbonates and Carbon Storage Research Centre (QCCSRC), provided jointly by Qatar Petroleum, Shell, and Qatar Science & Technology Park. Qatar Petroleum remain copyright owner."
Access the dataset https://www.bgs.ac.uk/services/ngdc/accessions/index.html#item118273
Further information Liyanage et al. Multidimensonal observations of dissolution-driven convection in simple porous media using X-ray CT scanning. Transport in Porous Media. DOI: 10.1007/s11242-018-1158-3