Hostname: page-component-cd9895bd7-lnqnp Total loading time: 0 Render date: 2024-12-20T22:31:34.589Z Has data issue: false hasContentIssue false

Magnetic resonance imaging of structure and convection in solidifying mushy layers

Published online by Cambridge University Press:  29 March 2006

PASCALE AUSSILLOUS
Affiliation:
Institute of Theoretical Geophysics, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK
ANDREW J. SEDERMAN
Affiliation:
Magnetic Resonance Research Center, Department of Chemical Engineering, University of Cambridge, Madingley Road, Cambridge CB3 0HE, UK
LYNN F. GLADDEN
Affiliation:
Magnetic Resonance Research Center, Department of Chemical Engineering, University of Cambridge, Madingley Road, Cambridge CB3 0HE, UK
HERBERT E. HUPPERT
Affiliation:
Institute of Theoretical Geophysics, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK
M. GRAE WORSTER
Affiliation:
Institute of Theoretical Geophysics, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK

Abstract

We have used magnetic resonance imaging to study the structure of and convection within a solidifying mushy layer formed from an aqueous sucrose solution cooled from above. We focus on the situation in which dissolution channels, known as chimneys, are created by the action of buoyancy-driven convection. We have obtained high-resolution images of the microstructure formed by individual ice platelets and coarser-grained images that average over the platelets to show the geometry of the dissolution channels. We observe that the chimneys are branched and occur only in the lower part of the mushy layer. By acquiring low-resolution images rapidly, we have made detailed measurements of the thickness of the mushy layer, its porosity distribution and the number and total area of the chimneys. The mushy layer is seen to grow in a self-similar manner until internal convection begins, whereafter the solid fraction increases in the lower part of the layer.

Type
Papers
Copyright
© 2006 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)