Visualization of Vapor Diffusion in External Thermal Insulation Materials Systems

Abstract

Visualization of vapor diffusion processes in external thermal insulation materials systems were tried. An idea of setting service life of these systems is shown when overall heat transfer coefficient increases to 120% from the initial value (thermal insulation performance reduces to 83%). It is shown that it is much influenced by water contents in the heat insulating materials. Based upon the modelling of unsteady state diffusion of external vapor into short-cut fiber reinforced cement composites(FRC) and thermal insulators, mathematical formulation of the progress of vapor concentration was done. On the other hand, numerical analysis was done, and the processes were shown by third and second dimensional picture images. This research is helpful as setting methods of service life of these materials systems.