Characteristics of mixing enhancement achieved using a pulsed plasma synthetic jet in a supersonic flow

Abstract

Supersonic mixing layers exist extensively in supersonic engineering applications. The rapid mixing of fuel and oxidant at short distances is of great importance, but makes it difficult to develop efficient propulsion systems. The plasma synthetic jet (PSJ) is regarded as a promising high-speed flow control technique. The characteristics of mixing enhancement achieved using a pulsed PSJ were investigated via experiments. Results showed that the PSJ is an effective method for mixing enhancement. Nanoparticle-based planar laser scattering (NPLS) was used to obtain flow structures in three directions. The velocity fields near the PSJ actuator orifice were measured by particle image velocimetry (PIV). Indexes of the fractal dimension and mixing layer thickness were applied to estimate the effect of the PSJ actuator on the supersonic mixing layers. The large-scale vortex structures induced by the pulsed PSJ in the supersonic mixing layers were successfully captured by NPLS. The effect of the PSJ on the supersonic mixing layers was remarkable. The mixing layer thickness under perturbation was larger than that under no perturbation in the downstream. The distribution of the fractal dimension suggests that perturbation of the PSJ cannot improve the fractal dimension values of the fully developed supersonic mixing layers.