Plasma synthetic jet actuator (PSJA), which produces pulsed jets, is used to control the shock wave boundary layer interaction at a compression ramp at Ma=2.0. The flow topology of the wall jets from the PSJA is first visualised through particle laser scattering (PLS) photography. The PSJA aperture effect is also examined by comparing the jets out of the apertures of 1,2 mm and 2 mm respectively. The control effect is later investigated by both PLS and particle image velocimetry (PIV). , which was erupted from different jet apertures of 1.2mm and 2mm, were compared experimentally in a wind tunnel of Mach 2. Further, the interaction between the TPJ and the ramp induced separation was explored. The phase-locked two-component particle image velocimetry (PIV) and particle laser scattering (PLS) were used for flow visualizations. The K-H vortices and hairpin vortices due to the shear stress between the jet plume and high-speed mainstream were identified.The results show that the TPJ in supersonic flow is characterized by two typical parts: the attached jet plume (AJP) and the detached jet plume (DJP). The penetration height of the jet plume, which is closely related to the jet aperture, plays a dominant role in the proportion of the two parts. The higher jet penetration height leads to the more detached jet plume. As for the interaction between the jet plume and separation zone, the attached jet plume was blocked by the separation zone, which formed a recirculation zone and contributed to an expansion of the separation. In contrast, the detached jet plume transited along the shear layer and then enhanced the velocity exchange between the shear layer and mainstream. Ultimately, the reduction of the separation zone was revealed with the overall shear layer reduced. Furthermore, a conceptual model based on two typical morphological features was suggested to reveal the interaction mechanism.

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Measurement on the minimum ignition energy (MIE) of n-decane with pyrolysis is investigated experimentally. Certain decomposition rate n-decane vapor is simulated by blending certain proportion of ethylene into n-decane vapor. Two equivalence ratios (1 and 0.7) and five blending ratios (0,0.2 0.4,0.6,0.7) of ethylene are, respectively, designed to represent different decomposition rates and equivalence ratios. The effect of different decomposition rates and equivalence ratios on the MIE of n-decane is investigated in following experiments. Two experimental methods are used for measurement. Technique of high-speed schlieren system is adopted to obtain images of the flame kernel by which the relationship between flame kernel radius and flame speed is calculated. An ignition probability model based on the logic regression theory is established to obtain the ignition probability curve. Results indicate that MIE is sensitive to the blending ratio of ethylene when equivalence ratio is 0.7. With elevated blending ratio of ethylene, MIE decreases rapidly firstly and with the continuous increasing of the blending ratio, the decreasing of MIE is lagging which indicates that there is a limit to the effect of the blending ratio of ethylene on the MIE. It is also found that values of MIE are closed when ethylene blending ratio is big enough whatever the equivalence ratio is.