EVENT DETAILS AND ABSTRACT

Title: The interior of mushy layers revealed
Speaker: Prof. M. Grae Worster
Speaker Info: Cambridge, UK
Brief Description:
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Abstract:

Mushy layers are two-phase, two-component, reactive porous media that occur commonly during the solidification of multi-component liquids, such as sea water, to form sea ice, or metallic alloys during casting. As melt percolates through the mushy layer, driven by buoyancy forces and transporting heat and solute, the solid phase of the medium evolves by dissolution or precipitation, which in turn changes the permeability of the medium and affects the flow. In particular, fluid-filled channels (chimneys) can form by dissolution and focus the flow into narrow regions. Our understanding of the formation, evolution and consequence of such channels has advanced significantly over the past couple of decades by a combination of laboratory experiments and applied mathematical modelling. Visual observation of the dynamic evolution of these systems has been of utmost importance in these developments, and has recently been augmented by using Magnetic Resonance Imaging (MRI) to reveal the internal microstructure as it changes in time. I shall describe both the theoretical and experimental studies of mushy layers and explain how fluid flow within them affects both their microstructure and the macroscopic development of solidifying systems.