- Author
- Miller, M. S.
- Title
- On the Ideality of Using a Step-Function Current in a Metallic Foil to Simulate a Step-Function Heat-Flux Source. Final Report. January 1992-February 1992.
- Coporate
- Army Research Laboratory, Aberdeen Proving Ground, MD
- Journal
- Journal of Applied Physics, Vol. 72, No. 9, 3904-3907, 1992
- Report
- ARL-MR-65, May 1993, 21 p.
- Keywords
- heat flux | thermal diffusivity | thermal diffusion | conductive heat transfer | thermal conductivity
- Identifiers
- transient heat conduction; metal foil; Laplace transform
- Abstract
- An exact solution is derived to the one-dimensional, time-dependent, heat-conduction equation for a two-layer, semi-infinite, composite solid with sudden uniform heat generation in the surface layer, no heat transfer through the surface plane, and uniform initial temperature. The interface between the two layers is assumed to have no thermal contact resistance. This solution enables a discussion of the ideality with which a step-function electric current in a metallic foil can generate a step-function heat flux into a contacting semi-infinite solid. Previous measurements of thermal diffusivity (based on the above conditions) have relied on the idealized constant-flux solution for data reduction. It is shown here that the temperature errors in the substrate arising from non-ideality of the constant-flux boundary condition increase with depth into the substrate, foil thickness, and decreasing thermal conductivity/diffusivity of the substrate.