Measurement of thermal diffusivity with a modified Angstrom method

A methodology has been developed to measure the thermal diffusivity of high thermal conductivity solid materials. The basic idea traces back to the Ångström method, but the implementation differs in some points. Originally the specimen was free to the environment, here the specimen is thermally insulated to reduce, and control, the effects of natural convection. An appropriate analytical solution is used to calculate temperature distribution. The original two-point approach is replaced by a parameter estimation technique to consider multiple measurement points and reduce the final uncertainty. The methodology is used for a pure copper bar. The results are compared with the data available in the literature. The measured thermal diffusivity is 1.16±0.07·10-4m2/s while the most reliable data available in the literature is 1.17±0.04·10-4m2/s. The agreement of the present value with those available in the literature is excellent. This makes the use of this simple analytical approach attractive.