Development of plasma actuators for re-ignition of aeroengine under high altitude conditions

Re-ignition of aeroengine under high altitude conditions is of great importance to the
safety and use of lean-burn engines. The present work investigated the experimental and
numerical analysis of flow and re-ignition characteristics in a rectangular burner. A ring-needle
type plasma actuator was developed and powered by high voltage nanopulsed plasma generator
with different percentage values of amplitude voltage and frequencies. Flow visualizations by
using high speed camera and Proper Orthogonal Decomposition (POD) were performed to
recognize the dominant flow structures. Experimental results showed the transport effects such
as induced flow with an impact on the recirculation zone near the corners of combustor,
improving the mixing performance, which could be contribute to the reduction of ignition
delay timings. Experimental characterization in non-reactive flow allowed the estimation of
the electrical power and the optimal reduced electric field (EN) value, which was then used as
input to the numerical study for the flame ignition analysis. Ignition characteristics were
analyzed by coupling two different numerical tools ZDPlasKin and Chemkin. It was noticed
that time required to achieve the maximum flame temperature with plasma actuation is
significantly reduced in compared with autoignition timings (clean case). Maximum reduction
in ignition timings was observed at inlet pressure 1 bar (3.5×10-5 s) in respect to clean case
(1.1×10-3 s). However, as the inlet pressure is reduced, the ignition delay timings were
increased. At 0.6 bar flame ignition was occurred at 0.0048s and 0.0022s and in clean case and
plasma actuation case, respectively.