Numerical Simulation Of DBD Plasma Discharge Process And Aerodynamic Excitation Characteristics

With the continuous development in the field of aerodynamics,passive flow control technology is increasingly difficult to overcome the huge challenges arising in today's aerodynamic design work.Dielectric barrier discharge plasma actuator has been widely studied as an active flow control method.It has a wide range of prospects such as increasing lift and reducing drag of the aircraft,improving the stability margin of the compressor,improving the efficiency of the turbine,and suppressing the flow separation of the boundary layer.In recent years,the research on plasma discharge process has been continuously deepened.As an important means to study the discharge and flow process,numerical simulation method has obvious advantages in revealing the discharge mechanism and optimizing the excitation intensity.Therefore,it is of great significance to conduct numerical simulation of plasma discharge process and study of aerodynamic excitation characteristics.In this paper,a fluid model of drift-diffusion approximation is used to simulate the plasma discharge process,and the physical mechanisms such as chemical reactions,electric field migration,particle transport,and momentum transfer involved in the discharge process are comprehensively considered.We obtained the spatiotemporal variation characteristics of each component particle and electric field distribution during the discharge process and the volume force distribution induced by excitation.The numerical simulation results of the discharge process show that the discharge breakdown forms a plasma channel.In this process,the electron number density rises rapidly in a very short time and accumulates near the high-voltage electrode.At the same time,the generated charged particles affect the shape of the electric field distribution.This promotes the development of plasma channels downstream along the surface of the medium.Through the analysis of the induced volume force results,it is found that the plasma discharge process not only generates an accelerated volume force in the horizontal direction,but also has a volume force effect in the direction of the wall surface in the sheath area above the ground electrode.After that,the parameters of the dielectric barrier discharge plasma actuator were studied.We analyzed the influence of the electrode spacing,the relative dielectric constant of the insulating plate and the voltage amplitude on the discharge characteristics.The results show that the smaller electrode spacing will make the discharge develop more fully,and the distribution of the induced volume force is closer to the wall surface;the smaller dielectric plate dielectric constant is not conducive to the development of the discharge along the dielectric surface,and the larger dielectric constant will weaken the electric field strength and affect Volume force strength;larger voltage amplitude will result in higher discharge strength and the volume force distribution is close to the wall surface.The mechanism of dielectric barrier discharge plasma actuators in flow control and the effect of induced flow are hot topics in current research.In this paper,the plasma discharge model is used to numerically study the induced flow effect of the static flow field.The actuators induces the gas flow to generate a starting vortex,which eventually develops into a jet.The rapid energy release during the discharge process causes the local gas to rapidly rise in temperature,thereby generating a declining pressure wave.Finally,the effect of suppressing flow separation when the plasma actuators is installed at different chord lengths of the NACA 0015 airfoil was studied.It was found that when the excitation is applied at the leading edge and the intermediate position of the airfoil,the separation can be effectively suppressed,thereby improving the airfoil Lift and stall angle of attack.