High frequency AC electric glow discharge visualization technology and application in big diameter hypersonic low-density wind tunnel

Wanqiu Jiang,Jie Wang,Chunman Mao,Jie Li,Zhengyi Long,Yilei Shi,Huacheng Qiu,Yanguang Yang

doi:10.1186/s42774-021-00067-w

Abstract

In order to visualize the rarefied flow field in a Φ1m hypersonic low-density wind tunnel, an electric glow discharge technique based on high frequency excited power has been developed. Firstly, finite element simulation analysis has been carried out, and it is concluded that the breakdown voltage can be reduced by using high frequency power supply; then an electric glow discharge apparatus has been fabricated, and the discharge images were compared with simulations; besides, a clear flow field around HB-1 standard model has been observed using this technology; finally, the influence of glow discharge on the flow field, as well as the differences between direct current and high frequency electric glow discharges is discussed at the end of this paper.

Highlights

Flow visualization has a major influence on fluid mechanics
Like particle image velocimetry [5] and planar laser scattering [6], suffer from the fact that the momentum transfer between the flow and the tracer is not sufficient, so that tracking particles cannot accelerate enough and are not representative of the flow velocity. It is in this range of rarefied gas flows that a visualization of the flow can be achieved by making use of the radiative characteristics of some gases
When the discharge method is applied to an accelerated flow or an unsteady flow in which there exist various kinds of external forces, glow plasma cannot track gas flow because of the difference of densities of the ionized gas particle and surrounding gas

Summary

Introduction

Flow visualization has a major influence on fluid mechanics. Several reviews and classifications of flow visualization techniques in fluid mechanics can be found in [1,2,3]. Like particle image velocimetry [5] and planar laser scattering [6], suffer from the fact that the momentum transfer between the flow and the tracer is not sufficient, so that tracking particles cannot accelerate enough and are not representative of the flow velocity. It is in this range of rarefied gas flows that a visualization of the flow can be achieved by making use of the radiative characteristics of some gases. Compared to the electron beam fluorescence setup, the electric glow discharge visualization appears to be a much simpler technique [9]

Methods

Conclusion