Ice Melting Kinetics in Sand–Water Mixtures Investigated by Neutron Radiography and Diffraction

Abstract

A combination of thermal neutron radiography and time-of-flight neutron diffraction is applied to analyze ice melting kinetics in sand–heavy water mixtures. Two different temperature regimes are applied: (1) cooling down to 262 K followed by spontaneous melting at room temperature (neutron radiography) and (2) cooling down to 250 K followed by controlled linear heating (neutron diffraction). Coarse and fine quartz sand batches are tested with the diameter of grains within the range 630–1,250 and 100–630 m, respectively. The solid–liquid transition temperature is observed to be significantly higher for the tested mixtures than for the sample containing pure heavy water only. A similar increase in the melting point of the mixtures relative to pure heavy water was observed by both of the applied methods. The enhancement amounted to 3 and 6 K in the case of the coarse and fine-grained samples, respectively. Grain size–dependent change in heat transport through the volume of the tested sand–heavy water ice mixtures is suggested as the main physical process behind the observed effect.