TY - JOUR
T1 - Effects of an annular plasma actuator on a co-flow jet downstream of a bluff-body
AU - Chen, Jun Lin
AU - Liao, Ying Hao
N1 - Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/6/25
Y1 - 2021/6/25
N2 - The present study is to experimentally investigate flow interactions downstream of a bluff-body incorporated with an annular plasma actuator, potentially for flame stabilization application. The dielectric-barrier discharge (DBD) actuator, flush with the bluff-body, is operated with AC in both sine and square waves, creating an inward flow and facilitating air entrainment to the jet. Electrical measurements show the larger peak current and the higher dissipation power in square wave, in which the high variation rate of voltage favors the electron escape from the dielectric surface, resulting in a stronger discharge. In addition, a more diffusive discharge accompanied with a larger peak current is observed in the negative half-cycle while filament discharges are present in the positive half-cycle. The plasma-induced flow is confirmed to be positively charged due to the flow deflection in a lateral DC electric field. Schlieren imaging and particle image velocimetry (PIV) show that as the actuator is activated, the jet at low Reynolds number is more susceptible to develop into turbulence and a vortex ring, due to the secondary low-pressure region induced by the actuator, is formed downstream of the bluff-body. The vortex ring is advantageous to active flow control, and is shown to enhance flame stabilization.
AB - The present study is to experimentally investigate flow interactions downstream of a bluff-body incorporated with an annular plasma actuator, potentially for flame stabilization application. The dielectric-barrier discharge (DBD) actuator, flush with the bluff-body, is operated with AC in both sine and square waves, creating an inward flow and facilitating air entrainment to the jet. Electrical measurements show the larger peak current and the higher dissipation power in square wave, in which the high variation rate of voltage favors the electron escape from the dielectric surface, resulting in a stronger discharge. In addition, a more diffusive discharge accompanied with a larger peak current is observed in the negative half-cycle while filament discharges are present in the positive half-cycle. The plasma-induced flow is confirmed to be positively charged due to the flow deflection in a lateral DC electric field. Schlieren imaging and particle image velocimetry (PIV) show that as the actuator is activated, the jet at low Reynolds number is more susceptible to develop into turbulence and a vortex ring, due to the secondary low-pressure region induced by the actuator, is formed downstream of the bluff-body. The vortex ring is advantageous to active flow control, and is shown to enhance flame stabilization.
KW - Bluff-body
KW - Dielectric-barrier discharge actuator
KW - Flame stabilization
KW - Plasma actuator
KW - Plasma synthetic jet
UR - http://www.scopus.com/inward/record.url?scp=85104678344&partnerID=8YFLogxK
U2 - 10.1016/j.applthermaleng.2021.116975
DO - 10.1016/j.applthermaleng.2021.116975
M3 - Article
AN - SCOPUS:85104678344
SN - 1359-4311
VL - 192
JO - Applied Thermal Engineering
JF - Applied Thermal Engineering
M1 - 116975
ER -