Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN CD: 1-56700-226-9

ISBN Online: 1-56700-225-0

International Heat Transfer Conference 13
August, 13-18, 2006, Sydney, Australia

STRESSES AND STRAINS IN THE FREEZING OF SPHERE SHAPED FOODS

Get access (open in a dialog) DOI: 10.1615/IHTC13.p29.80
9 pages

Abstrakt

When water freezes, its volume expands by about 9% creating severe stresses and strains. As water turns into ice, it forms a shell which restrains further expansion of the yet unfrozen water in the core. At some point, micro-cracks may form and the ice shell may flow plastically to relieve the stress. With rigid solid foods such as some fruit and tubers, another mechanism may take place where the food freezes and expands, causing tension in the core (instead of compression). These models give very different predictions of stress, strains and mechanical damage in the food. The paper presents models of the mechanical effects of phase change and contraction in a spherical food, and results of a preliminary investigation using photographic techniques to follow the volume changes caused by freezing.