Solidification in the Presence of Natural Convection in a Hele-Shaw Cell - Selected Topics of Computational and Experimental Fluid Mechanics - page 359

Solidification in the Presence of Natural
Convection in a Hele-Shaw Cell

G. Ramírez, J.E. Cisneros, G. Hernández Cruz and E. Ramos

Abstract The solidification of water with particles in a suspension that fills the
gap in a Hele-Shaw cell has been experimentally studied by visualization and using
particle image velocimetry (PIV). The upper wall of the cell is kept at a temperature
lower than 0 ⓦ C, while the lower wall is exposed to ambient temperature. Water
starts solidifying near the upper wall of the cell, and a solidification front moves in
the downward direction. Since the temperature gradient established is unstable in the
gravity acceleration field, the liquid acquires a natural convective motion, and the
solidification and convection interact with each other. The growth of the solidification
region in the Hele-Shaw cell modifies the volume available to the liquid and in this
way determines the convection pattern. In turn, the convective flow of the liquid
is an efficient heat pump at the liquid-solid boundary, and determines the velocity
and geometry of the solidification front. We present quantitative data of the velocity
and shape of the solidification front and the velocity field in the liquid region as
functions of time. We have found that the convective motion stops when the aspect
ratio (height/width) of the liquid region is approximately 0.45 and from this time on,
the motion of the solidification front follows Stefan's law.

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