Modeling of Heating Process in Layered Material due to Absorption of Unsteady Radiation

Radiation of various types passing through a material is partially or completely absorbed by it, which leads to an increase in temperature, especially in the surface layers. A model is proposed for calculating the temperature arising due to the absorption of radiation energy by a body with a single-layer or multilayer coating. The materials of the layers differ in their ability to absorb radiation energy, thermal properties, density and thickness. The body is exposed to periodic radiation, the time dependence of which is described by a Heaviside-type function. Heat is removed on the surface due to convection. The one-dimensional problem is considered. The body is modeled by a half-space with surface layers. Solution is based on the Laplace transform, reducing the problem to a system of linear algebraic equations and numerical inverse transform. Dependence of the temperature field on the input parameters of the problem is analyzed; for generality, the results are obtained in dimensionless form. It is obtained that the increase and decrease in temperature synchronously with the radiation period at the beginning of the process continues with heating and stabilization provided by convection. The model can be used to select radiation-protective coating materials, their combinations and layer thicknesses.