Abstract
Abstract
Recently, electric power equipment manufacturers released a joint statement with the aim of developing high-voltage electrical equipment completely free of fluorinated gases such as fluoroketones and fluoronitriles, which are considered as alternatives to
S
F
6
and artificially produced compounds of F. This paper considers air as a typical gas present naturally in the environment to investigate its high-temperature properties, including an air mixture with
C
2
F
4
vapor injected from a polytetrafluoroethylene nozzle, for application as an arc-quenching medium in a high-voltage circuit breaker equipped with a nozzle. Chemical composition results for the reaction products at 300–3000 K show that the admixture of
C
2
F
4
vapor causes a decrease in the molar number of
O
2
contained in the air, owing to the production of O-containing compounds such as
C
O
2
and
C
O
. Additionally, the results reveal that the admixture of
C
2
F
4
vapor lead to the production of
C
F
4
as the predominant F-containing compound. Furthermore, the boundary condition for
O
2
production in terms of
O
2
molar number
X
O
2
and
C
2
F
4
molar number
X
C
2
F
4
is formulated. Such evaluation of the mixture composition enables the determination of a reduced effective collision ionization coefficient
α
ˉ
/
N
and a critical reduced electric field strength
E
c
r
/
N
, resulting in
α
ˉ
/
N
= 0. The strength
E
c
r
/
N
for the mixture with 30%–100%
C
2
F
4
molar fraction rises to approximately 150 Td (1 Td = 1
×
10
−
21
V m2) over 300–3000 K, which is 20–50 Td higher than that for high-temperature air unmixed with
C
2
F
4
vapor. The variation in
E
c
r
/
N
is discussed in terms of predominant electron impact processes and the electron energy distribution function in the mixture.