An approach to calculate transient heat flow through multilayer spherical structures

The transmission matrix and frequency characteristics of transient heat conduction through a multilayer spherical structure are presented by applying Laplace transforms in this paper. The frequency domain regression (FDR) [S.W. Wang, Y.M. Chen, Appl. Thermal Engrg. 21 (6) (2000) 683] method is introduced to construct some simple polynomial s-transfer functions from the frequency characteristics. The polynomial s-transfer functions are further used to calculate the transient heat flow of the spherical structure including its thermal response factors and Z-conduction transfer function (CTF) coefficients. This approach is very easy and simple to implement in programming and avoids the case of missing roots in finding the roots of characteristic equation. The examples and comparisons have demonstrated that this approach has high computation accuracy.