Data reduction for k and α from transient heating of slab

Abstract

For the transient heat conduction of a thin slab, the temperature-time history of its mid-point can be determined from a plane wall theory, provided that a slab thickness to length ratio of 0.2 or smaller is used in the experiments. Using the theory, two data reduction methods are described for deducing the thermal properties of conductivity (k) and diffusivity (α) simultaneously from a single transient heating experiment. The first method uses an analytical technique to fit the inflection point on the temperature-√t, history plot to the theoretical inflection point. The second method, which was earlier proposed by the authors, uses a statistical curve fitting procedure to obtain the best fit between theory and experiment over seven points on the temperature-time history. Comparisons of the k values obtained by these methods against steady-state heat conduction measurements of the same slabs for various building construction materials indicate good agreement, and give support to the validity of these procedures. The values of k and α obtained by these procedures also compare favourably with reported literature data. © 1994.