TITLE:
Experimental Investigation on the Plasma Torch Used for Scramjet Ignition Enhancement
AUTHORS:
Wenli Zhong, Wenxiong Xi, Liwei Duan, Qingyao Xu, Qian Li
KEYWORDS:
Plasma Torch, Supersonic Flow, Schlieren Technology, Emission Spectroscopy, Shock Wave
JOURNAL NAME:
Journal of Applied Mathematics and Physics,
Vol.3 No.8,
August
26,
2015
ABSTRACT: A high frequency arc discharge plasma torch
was specially designed for ignition enhancement in scramjet combustor. At
first, the process of plasma injection into quiescent air was investigated
experimentally through CCD camera and schlieren technology. Then, the energy
property characterization of active particle distribution was measured by emission
spectrometry. Several kinds of working gas under different injection pressures
were compared. Finally, the typical supersonic flow-field structure with plasma
cross-injection was obtained. The results show that plasma jet energy is
concentrated near the jet axis, which has the maximum attenuation in the
downstream as far as 2 cm from the outlet. The working gas and injection
pressure have great effect on emission spectrometry and the process of jet
expansion. The case with N2 under higher injection pressure shows better
performance of energy exchanging process when comparing with air and argon.
From the emission spectroscopy, we can see that plasma from nitrogen consists
of nitrogen and oxygen atom mainly, whose intensity decreases with increasing
distance from the nozzle, while it increases with the increase of pressure.
When plasma was vertically injected into supersonic flow-field, bow shock wave
and mixing layer structure were formed with thicken mixing layer, which helps enhance
the mixing process between active particle and incoming air.