A Review on Dielectric Properties of Supercritical Fluids

Supercritical fluid (SCF), an intermediate state between gas and liquid, has been recently considered for being used as insulating media owing to properties that show exceptional dielectric strength, high heat transfer capability, and low viscosity. However, research on utilizing SCFs for power applications is still in its early stage, leaving literature and useful data on this topic very limited. This paper reviews and compares available literature related to the dielectric properties of SCFs, especially the electrical breakdown characteristics. Representative researches on the experimental demonstration of the discharge phenomenon in SCFs are summarized in this review. Important transport properties of SCFs, including viscosity, heat capacity, and thermal conductivity, are discussed. Furthermore, key parameters that define their dielectric properties, including conductivity and permittivity, are compared and summarized. Applications that require strong electric fields, efficient heat dissipation, and fast motion can benefit from using SCFs as a dielectric medium. The objective of this study is to provide a new perspective and useful recommendations on the selection of dielectric media for various practical purposes.