Abstract:
In this research, the finite-element method (FEM) analysis has been employed for the determination of the distribution of tissue temperature during microwave frequency radiation. The heat transfer intwo-dimensional (2D) multilayered human skin consisting of epidermis, dermis, subcutaneous and inner tissue exposed to microwave frequencieshas been analyzednumerically. Thefinite element method of Galerkin's weighted residual is employed to solve the governing system of equations (electromagnetic wave frequency and bio-heat(Pennes’ and thermal wave model) equations) with proper boundary conditions. The effects of different microwave power (from 10 to 25 W), heat flux(from 200 W/m2 to 600 W/m2), frequency (from 0.9 to 4 GHz), and time (from 1 to 960 s) on skin tissue have been examined in this simulation and displayed graphically in terms of the microwave power dissipation, isothermal lines inside skin tissue, point graph of temperature at different locations, relaxation time, specific absorption rate (SAR) and the surface average temperature of multilayer skin tissue. The results demonstrated that microwave power and frequency have significant impacts on the temperature distribution and SAR values of skin.Moreover, the tissue’s dielectric properties also affect the temperature distribution patterns within the body tissue. The findings also suggest that the inclusion of relaxation times in thermal analysis is of significant importance if the exposure duration is short. The effects of heat flux, microwave power, and frequency on the temperatures projected with different relaxation times are also investigated.According to thermal analysis results, Pennes’ equation gives higher predictions than that of the thermal wave model of bio-heat transfer (TWMBT).Thermal analysis of partial body exposure to the microwave was aimed by using TWMBT in this study, especially skin tissue, and it can be beneficial in widening the idea of clinical thermal technology and thermal medical practices such as lasers, and cancer hyperthermia.
