Heat Transfer And Thermal Stress During Cryopreservation Of Blood Vessel

Fracture have been reported in the wall of cryopreserved venous and arterial blood vessels. These fractures occur so frequently in human internal thoracic artery as to render convention cryopreservation methods useless. The aim of this study is to predict the fracture which may caused by thermal stresses during cryopreservation of fresh blood vessel. A thermal stress analysis model is developed for water freezing processes taking place inside a column. The model allows us to predict the temperature field and the thermal stress distributions in the ice. The maximum tensile stress occurs during phase change. The radial stresses are less than the circumferential stresses and the axial stresses. A quick freeing process results in larger thermal stresses in the ice than a slow freeing process does. If the maximum tensile stress exceeds the failure strength, the crack will initiate on the wall of blood vessel.