Effect of thermal relaxation time on heat transfer in a two layer composite system of living tissues

In this paper, we have numerically studied the heat transfer in a composite system of living tissues by taking into consideration the effect of thermal relaxation time. The composite system of living tissues comprises two layers in which the heat transfer takes place in one layer due to pure diffusion, while in the other layer due to both perfusion and diffusion. The modified Pennes bioheat equation is considered by introducing a thermal relaxation time which is the ratio of the thermal diffusion to the square of the heat propagation velocity in the medium. We assume that heat mainly propagates in the direction perpendicular to the skin surface. The problem is solved numerically by developing the Crank–Nicolson implicit finite difference scheme. With an aim to validate our numerical results, a comparison has been made with the previous solution and shows excellent agreement. The study shows that the relaxation time has a significant impact on the temperature distribution in a two layer composite system of living tissues.