On the measurement of the electric strength of gases at elevated pressures. III, hexane

It is generally accepted that electric breakdown in low density gases (e.g. hexane vapor) is completely described by the Townsend mechanism of breakdown¹. On the other hand, our recent studies using liquid hexane have shown that breakdown does not occur via a Townsend mechanism but rather by means of a thermal mechanism². It is therefore, of interest to make a systematic study in the intermediate range of densities where a transition from a Townsend to a thermal mechanism may be expected to occur. Accordingly, the electric strength of hexane vapor has been measured at temperatures near critical under conditions where the vapor density was continuously increased by pressure change up to the critical density. Young³ had previously made such a study in the critical region using carbon dioxide; however, it was desirable to repeat this experiment using hexane because of the large accumulation of breakdown data on liquid and gaseous hydrocarbons. We present in this paper, the results of such a study and a tentative analysis thereof.