抄録
The electrostatic levitation technique makes it possible to measure thermo-physical properties of extremely high-temperature molten materials. In the technique, viscosity of levitated sample has been estimated from the damping constant time with an oscillating drop method based on linear approximations. However, this method is limited to low-viscosity fluids because the oscillation could not be excited to a highly viscous liquid drop. The measurement method which can be applied to viscosity over the entire range possible has not been established yet. The main purpose of the present study is to investigate the possibility to measure viscosity of entire range with a levitating liquid drop. In the present study, viscous drops were levitated by the electrostatic force. The effect of viscosity on the deformation of a rotating liquid drop was experimentally investigated. As a result, the rotational deformation of a low-viscosity drop is found to be qualitatively similar to the numerical result. On the other hand, large differences from the numerical result are observed in the case of high-viscosity drops. It is confirmed especially that viscosity is closely related to the evolution of drop shape during the drop breakup process. From the experimental results, it is clarified that the viscosity of a levitating liquid drop can be estimated from the breakup behavior of the drop.
