Non-Fourier heat conduction effect on prediction of temperature transients and thermal stress in skin cryopreservation

To prevent loss of viability in cryopreserved skin tissue, one of the most important issues is to understand the thermal stress induced by cryopreservation. During skin cryopreservation, which involves instantaneous heat transfer in small scale under cryogenic temperature, the thermal wave effect in heat conduction is expected to be critical for predicting phase change and related events in skin tissue. But up to now, little is known about phase change heat transfer considering a non-Fourier effect; and most of the existing attempts were based on the calculation in infinite domain; in particular, the thermal stress thus induced in the phase change process with non-Fourier effect has not been reported. In this study, the phase change behavior and the thermal stress inside the skin tissue subject to freezing were numerically investigated considering the non-Fourier effect. The results obtained from the hyperbolic heat conduction equation were compared with those obtained from the classical parabolic heat conduction equation. It was shown that results from the non-Fourier model and the traditional heat conduction equation are quite different in some cases and that the non-Fourier effect can be important when the thermal relaxation time of biomaterials is large. Without considering this effect, error and misinterpretation of the predicted temperature and thermal stress may result.