Relationship between two solidification problems in order to determine unknown thermal coefficients when the heat transfer coefficient is very large

SALVA, N.N.; TARZIA, D.A.

APPLIED MATHEMATICS AND COMPUTATION

ELSEVIER SCIENCE INC

Año: 2024 vol. 468 p. 1 - 16

0096-3003

The phase-change processes are found in a wide variety of dynamic systems, for example in thestudy of snow avalanches. When a thermal property of the material is unknown, we can add aboundary condition to formulate an Inverse Stefan Problem, and determine this property. In thispaper we study a heat conduction phase-change problem with Robin and Neumann boundarycondition at a fixed face. This overspecified condition allows to simultaneously determine twounknown thermal coefficients through a moving boundary problem or a free boundary problem.Formulae for different cases where obtained by Ceretani and Tarzia (2015) [6]. The formulationwith these type of boundary conditions is a more realistic one than the heat conduction phase-change problems with Dirichlet and Neumann boundary condition at the fixed face, consideredby Tarzia, (1982-1983). Therefore we propose to study the relationship between the problemswith Robin-Neumann conditions, and the problems with Dirichlet-Neumann conditions. Themain result of this work is the convergence analysis of these problems, when the heat transfercoefficient ℎ of the Robin condition is very large. We present for each case of the free and movingboundary problems, an upper bound for the error of the two unknown parameters, obtaining inevery case a bound of order 𝑜( 1/h ). Finally we show a numerical example of the convergence, for aphase change material commonly used in heating or cooling processes.