Investigation of polymer composites interfacing pressurized airflow

This paper aims to characterize the polymer composites interfacing flowing air as a simulation of those used in large forced-gas cooled rotating machines and modern power transformers. Many factors have been investigated in order to show their effects on the current–voltage (I–V) characteristics. The results reveal that the air conditions play an important role in the I–V characteristics of polymer/flowing air/polymer gaps. The conduction current of such gaps increases with the increases in air-flow rate and temperature but it decreases with the increase in air pressure; especially at high temperature. It is also found that there is no significant effect of the combined-crossed ac magnetic field on the conduction current. Phenomenological explanations of the air–polymer–metal interfaces are introduced in the core of physicochemical reactions and injection processes. In addition, derivation of the dependence of volume charge density inside the test section on flow velocity is introduced, which interprets the trend of the experimental results.