A backward reciprocity function approach to estimate spatial transient themal contact conductance in double-layered materials using non-intrusive measurements

Numerical Heat Transfer (A), 68(2) (2015), 117-132
http://dx.doi.org/10.1080/10407782.2014.994435

This paper presents a methodology to estimate internal convective heat transfer coefficients in ducts, using only data available at an exterior boundary. The methodology is based on the reciprocity function approach, which was previously presented by the authors. Such method does not require any intrusive measurements and it needs low computational resources because it avoids the use of iterative techniques. The unknown function can be estimated solving a linear system, where the solution vector is composed of integrals of the boundary data. Numerical results are presented, where the stability of the method is tested against different functions, with high levels of noise. In the final part of the paper, a real test case, using measurements taken by an infrared camera, is analyzed and the method is compared against a well-known approach, based on the Tikhonov regularization scheme. Results are very good and the proposed method gives equivalent results to the ones obtained by the Tikhonov method.