Research On Active Flow Control Technology Based On Surface Dielectric Barrier Discharge

The high-speed railway has a large carrying capacity and fast speed,which can optimize the allocation and utilization of production and consumption factors between the high-speed railway and the urban agglomeration.This has great strategic significance for the development of our national economy.With the increase of the operating speed of high-speed railways,the problem of air resistance to trains has become increasingly serious.It has become one of the three major relationships(pantographs-catenary relationship,wheel-rail relationship,and fluid-structure coupling)that restrict the development of high-speed railways.Plasma active flow control has the advantages of simple structure,good robustness,fast response time,etc.,and has great potential in improving aerodynamic characteristics.Therefore,research on plasma active flow control technology is of great significance for the safe and stable operation of trains and energy saving and emission reduction.On the one hand,from the theoretical point of view,this article analyzes the focus and difficulties of current plasma research.At present,the induced airflow obtained by a singlestage device is relatively small,and the energy utilization efficiency is low.How to increase the speed level of the induced airflow and energy utilization efficiency has been the focus of research in this field.In order to increase the velocity of induced airflow and the efficiency of energy utilization,a new electrode structure is designed based on the existing theoretical analysis,and an experimental analysis is carried out for this kind of filament comb electrode structure.In the voltage range of 20 k V to 26 k V,the effects on plasma discharge characteristics and induced airflow when it is used as an exposed electrode are studied from the aspects of voltage and current waveforms,discharge images,power loss,and induced airflow.The results are compared with those of a plate electrode.The experimental results show that the use of comb electrodes effectively controls the position of the plasma discharge,reduces the breakdown voltage,strengthens the discharge process,increases the induced airflow and energy utilization efficiency due to the tip effect.This study has a certain guiding effect in improving the structure of SDBD plasma device,increasing the speed of the induced air flow and energy utilization efficiency.On the other hand,the current researches on dielectric barrier discharges at home and abroad mostly focus on the volume force and the velocity of induced airflow,but the research on the discharge characteristics under their application conditions is insufficient.In order to scientifically design and arrange the discharge plasma flow control actuator,the effect of air flow on the dielectric barrier discharge at different voltages in the range of air velocity 0 ～20m / s is studied,and the mechanism of the effect of air flow on discharge is discussed.By measuring the discharge current and discharge voltage,the influence of air flow on the maximum discharge current and discharge power is analyzed.By collecting discharge images at different air flow velocities,the discharge intensity,discharge uniformity,and discharge form are analyzed.Based on this,the physical laws of SDBD in the airflow are comprehensively analyzed.The results show that as the airflow increases,the plasma discharge intensity decreases,the discharge becomes uniform,and the maximum discharge current and power decrease gradually.The research results have certain reference function for designing and arranging the plasma actuator to improve the performance of the device.