Three-layer thermal-diffusivity problem applied to measurements on mercury

Abstract

To adapt and apply the heat-pulse technique for thermal-diffusivity measurements to liquids, the one-dimensional three-layer heat conduction problem has been solved analytically with an adiabatic boundary condition on the front surface and both adiabatic and isothermal boundary conditions on the rear surface. Computed solutions of the three-, two-, and one-layer problems are compared to determine the relative effects of the front layer (window) and the rear layer (cell material) on the temperature pulse shape transmitted through the liquid layer. Measurements at several temperatures from 294 to 267°K on a mercury specimen are analyzed using these results and the deduced diffusivity values are compared with those given by the Thermophysical Properties Research Center.