Measuring dendritic growth in undercooled sucrose solution droplets

A simple apparatus for observing the dendritic growth in transparent solutions at high undercoolings is described. This method involves the suspension of a droplet on the junction of a thermocouple. With this method it is possible to measure the ice dendrite growth velocity and tip radius to the limit of stable dendritic growth in sucrose solutions. Good agreement was observed with previous growth velocity data. Analysis with the Lipton, Kurtz and Trivedi (LKT) dendritic growth model showed that at high undercoolings the dendritic growth in sucrose solutions becomes predominately thermally and kinetically controlled, whereas the kinetic growth becomes increasingly diffusion and viscosity limited with increasing undercooling and melt solute concentration. The results supported previously proposed changes to the LKT model to accommodate high undercoolings and changing melt diffusivity and viscosity.