New thermal wave aspects on burn evaluation of skin subjected to instantaneous heating

TLDR

Thermal wave theory may be extended to other medical problems involving instantaneous heating or cooling. The study compares Pennes' equation with a new thermal wave model (TWMBT) to investigate wave‑like bioheat transfer behaviors in thermal injury. The authors solved a one‑dimensional TWMBT analytically and used finite‑difference simulations on a three‑layer skin model to study burn injury heat transfer. TWMBT predicts realistic burn outcomes for flash‑fire heating, establishes a heat‑flux criterion for when wave propagation dominates, and offers a preliminary interpretation of wave‑like heat transfer mechanisms.

Abstract

Comparative studies on the well-known Pennes' equation and the newly developed thermal wave model of bioheat transfer (TWMBT) were performed to investigate the wave like behaviors of bioheat transfer occurred in thermal injury of biological bodies. The one-dimensional TWMBT in a finite medium was solved using separation of variables and the analytical solution showed distinctive wave behaviors of bioheat transfer in skin subjected to instantaneous heating. The finite difference method was used to simulate and study practical problems involved in burn injuries in which skin was stratified as three layers with various thermal physical properties. Deviations between the TWMBT and the traditional Pennes' equation imply that, for high flux heating with extremely short duration (i.e., flash fire), the TWMBT which accounts for finite thermal wave propagation may provide realistic predictions on burn evaluation. A general heat flux criterion has been established to determine when the thermal wave propagation dominates the principal heat transfer process and the TWMBT can be used for tissue temperature prediction and burn evaluation. A preliminary interpretation on the mechanisms of the wave like behaviors of heat transfer in living tissues was conducted. The application of thermal wave theory can also be possibly extended to other medical problems which involve instantaneous heating or cooling.