The C-axis growth rate of ice crystals

Abstract

An experimental investigation has been carried out into the C-axis growth rates of ice crystals growing from a capillary tip into a stream of brine or water inside a closely-controlled temperature bath. Results are reported for growth in water at flow velocities of 5 cm/s and 12.5 cm/s for bath sub-coolings ranging from 0.06 to 1.2 K. and for growth in brine of concentrations from 1 to 4% at a flow velocity of 5 cm/s for bath sub-coolings from 0.23 to 0.5 K. The fresh water growth rates are lower by an order of magnitude than earlier reported results at the same bath sub-coolings. The growth rates increase with stream velocity at high sub-coolings, suggesting boundary layer thermal resistance. When allowance is made for this effect, the growth rates plotted against surface sub-coolings are in closer agreement with the previously-reported data and confirm the two-dimensional nucleation mechanism. The salt water data indicate a decrease in C-axis growth rate with increase of salt concentration. At least part of this effect can be accounted for by salt build-up at the ice surface as the result of boundary layer diffusion effects.