Solution of an inverse problem of heat conduction by iteration methods

1974 ◽  
Vol 26 (4) ◽  
pp. 471-476 ◽  
Author(s):  
O. M. Alifanov
Author(s):  
Wit Stryczniewicz ◽  
Janusz Zmywaczyk ◽  
Andrzej Jaroslaw Panas

Purpose The paper aims to discuss the inverse heat conduction methodology in solution of a certain parameter identification problem. The problem itself concerns determination of the thermophysical properties of a thin layer coating by applying the laser flash apparatus. Design/methodology/approach The modelled laser flash diffusivity data from the three-layer sample investigation are used as input for the following parameter estimation procedure. Assuming known middle layer, i.e. substrate properties, the thermal diffusivity (TD) of the side layers’ material is determined. The estimation technique utilises the finite element method for numerical solution of the direct, 2D axisymmetric heat conduction problem. Findings The paper presents methodology developed for a three-layer sample studies and results of the estimation technique testing and evaluation based on simulated data. The multi-parametrical identification procedure results in identification of the out of plane thin layer material diffusivity from the inverse problem solution. Research limitations/implications The presentation itself is limited to numerical simulation data, but it should be underlined that the flake graphite thermophysical parameters have been utilised in numerical tests. Practical implications The developed methodology is planned to be applied in detailed experimental studies of flake graphite. Originality/value In the course of a present study, a methodology of the thin-coating layer TD determination was developed. In spite of the fact that it has been developed for the graphite coating investigation, it was planned to be universal in application to any thin–thick composite structure study.


2003 ◽  
Vol 125 (6) ◽  
pp. 1178-1183 ◽  
Author(s):  
F. Alhama ◽  
J. Zueco and ◽  
C. F. Gonza´lez Ferna´ndez

This work addresses unsteady heat conduction in a plane wall subjected to a time-variable incident heat flux. Three different types of flux are studied (sinusoidal, triangular and step waveforms) and constant thermal properties are assumed for simplicity. First, the direct heat conduction problem is solved using the Network Simulation Method (NSM) and the collection of temperatures obtained at given instants is modified by introducing a random error. The resulting temperatures act as the input data for the inverse problem, which is also solved by a sequential approach using the NSM in a simple way. The solution is a continuous piece-wise function obtained step by step by minimizing the classical functional that compares the above input data with those obtained from the solution of the inverse problem. No prior information is used for the functional forms of the unknown heat flux. A piece-wise linear stretches of variable slope and length is used for each of the stretches of the solution. The sensitivity of the functional versus the slope of the line, at each step, is acceptable and the complete piece-wise solution is very close to the exact incident heat flux in all of the mentioned waveforms.


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