Evaluation of the Effective Sample Temperature in Thermal Diffusivity Measurements Using the Laser Flash Method

In the measurement of thermal diffusivity by the laser flash method, a temperature rise occurs in the sample as a pulsed laser hits on the sample surface. Due to the temperature dependence of thermal diffusivity of the sample, the thermal diffusivity corresponds to a temperature that is larger by Teff than the temperature before laser irradiation is applied. This effective temperature rise, Teff , has been investigated by using a numerical simulation. The results indicate that the effective temperature rise is almost equal to a maximum temperature rise, TM, of the back surface of the sample in cases where both linear and nonlinear temperature variations of thermal diffusivity are considered.