A study on the non-Fourier effects in spherical media due to sudden temperature changes on the surfaces

The non-Fourier effects on the dynamic thermal behavior of spherical media, including solid, hollow and bi-layered composite spheres, due to sudden temperature changes on the surfaces are investigated. The temperature and heat flux histories in the spherical media are predicted by an analytical–numerical technique. The speed of heat propagation is finite, as revealed in the temperature and heat flux calculated by using the hyperbolic heat-conduction equation. Effects of different parameters such as the relaxation time, the imposed temperature ratio on the inner and outer layers of the hollow sphere, the thermal diffusivity ratio, and the relaxation time ratio of the composite sphere are studied and presented.