A review on simultaneous determination of thermal diffusivity and heat transfer coefficient

Mathematical simulation studies for thermal food processes require knowledge of thermal diffusivity and convective heat transfer coefficient. There have been different experimental and empirical approaches reported in the literature for determination of these parameters where different approximations were applied. One of the most applied approaches is to assume an infinite convective heat transfer coefficient at the surface boundary when analytical solutions for infinite slab, infinite cylinder and sphere are used for further determinations. Since this approach results in certain errors in results, it would be an important task to determine thermal diffusivity and convective heat transfer coefficient simultaneously. Therefore, the objective of this study was to review the literature for determination of thermal diffusivity and mathematically apply optimization methodologies for simultaneous determination of heat transfer coefficient. For this purpose, constrained optimization methodologies, based on analytical solutions of infinite slab, infinite cylinder and sphere were defined, and results were discussed intensively. The results showed that a precise determination of thermal diffusivity and convective heat transfer coefficient is a difficult task, but knowing the location where the experimental time-temperature was obtained would really simplify this problem. (C) 2007 Published by Elsevier Ltd.