Determination of the Thermal-Diffusivity and Specific-Heat Using an Exponential Heat Pulse, Including Heat-Loss Effects

TitleDetermination of the Thermal-Diffusivity and Specific-Heat Using an Exponential Heat Pulse, Including Heat-Loss Effects
Publication TypeJournal Article
Year of Publication1989
AuthorsVining, C. B., A. Zoltan, and J. W. Vandersande
Journal TitleInternational Journal of Thermophysics
Volume10
Issue1
Pages259-268
Journal DateJan
Accession NumberISI:A1989U421900022
Keywordseffective time constant, exponential heat pulse, Ge-Si alloys, Heat capacities of solids [A6540], heat-loss effects, homogeneous body, Nonelectronic thermal conduction and heat-pulse propagation in nonmetallic solids [A6670], one-dimensional heat diffusion equation, semiconductor, Semiconductor materials, specific heat, Specific heat of solids, Thermal diffusivity, Thermal instruments and techniques [A0720]
Abstract

The one-dimensional heat diffusion equation has been solved analytically for the case of a heat pulse of the form F(t)=exp(-t/ tau )/ tau applied to the front face of a homogeneous body including the effects of heat loss from the front and back faces. Approximate expressions are presented which yield a simple, accurate technique for the determination of the thermal diffusivity and specific heat, suitable to a wide range of heat-pulse time constant and heat-loss parameters, without recourse to graphical techniques or requiring further computer analysis. A procedure is described for the determination of an effective time constant to allow application of the present results to the case of a nonexponential heat pulse. Experimental results supporting the theoretical analysis are presented for five samples of silicon germanium alloys of various thicknesses, determined using a xenon flash tube heat-pulse exhibiting an exponential dependence. Proper consideration of the experimental heat pulse shape is shown to lead to reliable corrections to the apparent thermal diffusivity, even for relatively long heat-pulse times. (14 References).

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Citation Keyvining1989-4
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