Experimental Study On Plasma Flow Control Of Surface Dielectric Barrier Discharge

With the booming development of the transportation industry,the running speed has been steadily increasing,resulting in an intensified interaction between the vehicles and the air,which worsen the problems of fluid-solid coupling.The aerodynamic characteristics of moving parts and the energy utilization efficiency of power devices have become the key issues to be solved in the transport field.At the same time,thanks to the deepening study of aerodynamics,the boundary layer theory has attracted extensive attention in solving aerodynamic characteristics,providing abundant theories for flow control technology.As a new type of active flow control technology based on plasma aerodynamic excitation,surface dielectric barrier discharge has many advantages including small size,simple structure,fast response and so on,which has great potential to improve the boundary layer characteristics and optimize the aerodynamic characteristics of moving parts,showing a promising application prospect in the flow control field.At present,the key to optimize the design and improve the flow control capability of SDBD plasma actuator is to strengthen the induced airflow velocity,reduce the power consumption and further improve the energy utilization efficiency.With the purpose of promoting the application of plasma actuator in practical engineering,it is of great significance to investigate the change rules and action mechanism of different parameters on SDBD characteristics.Taking the plasma flow control as the background,this thesis conducted research based on the plasma experimental apparatus and comprehensive parameter diagnosis equipment.Firstly,the power parameters were studied,focused on the influence of the supply voltage on the discharge characteristics of the SDBD actuator,and the aspects of discharge waveforms,plasma morphology,power consumption,and mechanical efficiency were considered to analyse voltage operating range of the experimental power supply for optimal performance.Meanwhile,based on different dielectric materials,the research on the impact of working frequency on SDBD actuator performance was carried out,and the onset voltage and sustain voltage are analyzed to determine the optimal working frequency.Secondly,focused on the composite dielectric composed of PI film/glass,the effects of discharge performance and mechanical characteristics of SDBD actuator were investigated and compared with single glass dielectric.Combined with the theory of interface polarization of two-layer dielectric and the accumulated charge characteristics,a theoretical analysis was performed to clarify the mechanism of the influence of the composite dielectric on the discharge characteristics of the SDBD actuator.The results indicated that the energy utilization efficiency of SDBD actuator can be effectively improved by composite dielectric.Furthermore,based on the three electrode configurations,the influence of geometry of the buried electrode on discharge and aerodynamic characteristics of SDBD actuator was studied.The effects of optical characteristics,electrical performances and mechanical properties were compared.Mechanisms of the buried electrode geometry influencing these key characteristics were discussed from the point of equivalent circuit model and gray frequency distribution.The results illustrated that electrical power consumption is not a decisive parameter for induced airflow,instead,the extended region of glow discharge has a prominent influence on it.This thesis has a guiding significance in optimizing the design of SDBD actuator and deepening the understanding of the mechanism of discharge and induced airflow generation on SDBD,and futher promoting the application of SDBD plasma flow control technology in practical engineering.