Effect of working gas on the flow inclination sensor with two-wire spherical structure

In this paper, the effect of three favorite sensitive working gas, dry air, N
₂
and He, on the sensitivity of flow inclination sensor with two-wire spherical sensitive cavity is compared and studied. Using the finite element method, the temperature field, when at the inclination of 10°, in the sensitive element is calculated. The numerical results and experiments indicate that: (1) The distribution of temperature field is changing with the different sensitive working gas. (2) When the inclination θ=10°, the temperature difference of thermal resistance r
₁
and r
₂
, ΔT
_N2
>ΔT
_AIR
>ΔT
_He
. (3) The sensitive coefficient, K
_N2
> K
_AIR
> K
_He
, where the K
_N2
is 1.02 times of K
_AIR
and the K
_He
is 4.32% of the K
_AIR
. (4) The sensitivity is the highest when using N
₂
, the thermal resistance wire is antioxidant and the stability is good. But N
₂
is expensive. Compared to N
₂
, the sensitivity is lower when using dry air, the thermal resistance wire is easy to be oxidized and the stability is bad. Finally, the sensitivity is the smallest when using He, the thermal resistance wire is difficult to be oxidized and the stability is the best. This paper explained the influence mechanism of sensitive working gas on the sensitivity of flow inclination sensor with two-wire spherical sensitive cavity. This can enhance the practicability of flow inclination sensor with two-wire spherical sensitive cavity and can open up an novel method for satisfying the different engineering requirement.