Numerical solution of an inverse diffusion problem for the moisture transfer coefficient in a porous material

• Published in: Materials and structures Vol. 41; no. 2; pp. 335 - 344
• Main Authors: Amirkhanov, I. V., Pavlušová, E., Pavluš, M., Puzynina, T. P., Puzynin, I. V., Sarhadov, I.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.03.2008; Springer Nature B.V
• Subjects: Boundaries; Building construction; Building Materials; Civil Engineering; Coefficients; Diffusion; Engineering; Inverse; Machines; Manufacturing; Materials Science; Mathematical analysis; Mathematical models; Moisture; Original Article; Porous materials; Processes; Solid Mechanics; Studies; Theoretical and Applied Mechanics; Neutron radiography; Newton method of functional minimization; Finite-difference approximation; Moisture diffusion profiles; Moisture transfer coefficient; Nonlinear diffusion equation
• ISSN: 1359-5997; 1871-6873
• DOI: 10.1617/s11527-007-9246-9

On the basis of the solution of a nonlinear diffusion equation with initial and boundary conditions, a transfer coefficient of moisture in a sample of a porous material is found by minimization of a functional, which expresses error of the calculated profile of moisture concentration in well defined time moments from their experimental values for the defined moisture transfer coefficient. In this case the transfer coefficient as opposed to previous studies is found as a sum of a power function and an exponential function of the moisture concentration. The exponent of the power function depends on time. Thus, a more accurate coincidence of the calculated profiles of the moisture concentration to their experimental profiles is gained in comparison to the investigations performed by other authors. The exponential term provides a good coincidence of the mentioned profiles for big times nearby the boundary of the sample, where the moisture evaporation to the atmosphere takes place.