6

6

ASTM_6,6

[12]

Heat

transfer rate

ASTM_5,5

Thermal diffusivity (D_th) depends on heat transfer rate (q_H), according to the implicit function:

$\begin{array}{l}{D}_{th}={\alpha }_s=\left(\frac{z^2}{t}\right)\ast f(\left(\frac{{\rho }_s\ast z^4}{{\lambda }_s\ast T_i\ast t^3}\right),\left(\frac{z^2}{C_s\ast t^2\ast T_i}\right),\left(\frac{z^3}{V_s}\right),\begin{array}{c}\stackrel{}{}\\ \\ \end{array}\\ \left(\frac{T_i}{\left(\frac{\text{d}T}{\text{d}z}\right)\ast z}\right),\left(Bi\right),\left(\frac{z^2}{A}\right),\left(\frac{{\rho }_s\ast z^5}{t^2\ast q_H}\right))\end{array}$

Where the terms, definitions and dimensions of $\left(D_{th},z,t,{\rho }_s,{\lambda }_s,T_i,C_s,V_s,Bi,A,q_H\right)$ are presented in detail in the below terminology (Table A8) of the Appendix. For clarification purposes, (A) refers to specimen sectional area. Rayleigh’s method of indices was deployed along with the echelon matrix procedure as an additional confirmation method.