NMR verification of single droplet freezing models

Acquiring temporal solid/liquid fraction data of a freezing system is advantageous for verifying theoretical solidification models. Nuclear magnetic resonance (NMR) spectrometry was used to obtain liquid fraction data of droplets of either water or sucrose solution undergoing freezing. The data obtained were used to verify numerical models of this solidification process. For water droplets, good agreement was observed between the experimental and model predictions of the temporal change in the water fraction over the range of air temperatures studied, whereas for the sucrose solution good agreement was observed only at the highest air temperature. At lower air temperatures, the discrepancies of the model were attributed to the possible crystallization of sucrose at temperatures above its reported glass-transition temperature. (c) 2005 American Institute of Chemical Engineers.