Thermal imaging of time-varying longitudinal defects in the internal coating of a tube

Viene studiata l'evoluzione nel tempo del degrado del rivestimento interno di un tubo metallico al cui interno scorre un fluido. Il degrado si manifesta in tagli longitudinali del rivestimento. Per questo motivo il problema puo' essere posto e risolto (per mezzo di Thin Plate Approximation) in due dimensioni.

We deal with the mathematical model of the incremental degradation of the internal coating (e.g. a polymeric material) of a metallic pipe in which a fluid flows relatively fast. The fluid drags solid impurities so that longitudinal scratches, inaccessible to any direct inspection procedure, are produced on the coating. Time evolution of this kind of defects can be reconstructed from the knowledge of a sequence of temperature maps of the external surface. The time-varying orthogonal section of this damaged interface is determined as a function of time and polar angle through the identification of a suitable effective heat transfer coefficient by means of Thin Plate Approximation.