Verification of Convection Effect on Thermal Conductivity Measurement of Molten Metals by Hot-disk Method using Drop Tower

Microgravity circumstance is useful for measurement of thermal conductivity of molten metals, because thermal convection is suppressed. To measure the thermal conductivities of molten metals systematically under microgravity, it needs many chances for the microgravity experiments. The short-duration microgravity of drop tower experiments is suitable for this purpose. In this study, the thermal conductivities of several molten metals were measured by hot-disk method under short-duration microgravity of drop tower experiments to study the influence of convection, limitation of time and space. In addition, the thermal conductivities of molten metals without convection effect were compared with those derived from Wiedemann-Franz law. The thermal conductivities of Hg and Bi melts were good agreement with those derived from Wiedemann-Franz law, but those of Sn, Si and InSb melts were different from those derived from Wiedemann.Franz law.