Studies On The Plasma Actuator Used For Electrohydrodynamic (EHD) Flow Control

The electrohydrodynamic (EHD) flow control technology based on atmospheric plasma can directly convert electric energy to the kinetic energy of flow without involving moving mechanical parts; therefore, it holds a series of obvious advantages in complexity, vibration, abradability and so on, which render it extremely effective in the area of air flow control. Studies on the EHD plasma actuators have witnessed great progress these years; however, there are still many problems around it. First of all, the physical process of energy converting is still unclear and the theory of flow acceleration is still premature; secondly, the problems of flow direction and surface flash of plasma actuators remain unsolved; At last, the efficiency of EHD plasma actuators is still quite low. Therefore, in order to increase the efficiency of plasma actuators, how to choose the optimal parameters of them becomes the key question in the area of EHD flow control.Considering all the questions mentioned above, this paper mainly carried out a series of experiments and certain theory analysis in order to gain better understanding of all those questions. Firstly, this paper studied the low electrode-sealed and asymmetrical plasma actuators and then explored the theory of flow acceleration. Results shows that the efficiency of plasma actuator could be dramatically increased through sealing the low electrode of plasma actuators and the negative ion seems to play a positive role in the flow acceleration process; Secondly, this paper showed that sealing the panel could prevent the surface flash effectively and also could improve the performance of plasma actuators. When it comes to the question of flow direction, this paper measured both the vertical thrust and the vertical flow velocity of plasma actuators and results show that the vertical part of flow could be neglected.The many parameters of plasma actuators, such as the width of low electrodes, the gap of two electrodes and the voltage of energy source, all could influence the performance of plasma actuators to a great extent. Therefore, the paper explored the influence of all these parameters posed on the plasma actuator using experimental methods and then listed the optimal option of those parameters. Experiment results show that the influence of the width of low electrode W2 is ignorable and the efficiency of plasma actuator is highest when the gap d is about 2mm; the energy consumption increases monotonically with the voltage and frequency of the energy source but the flow generated does not increase monotonically at the same time; and when the plasma appears to be more uniform, the efficiency of plasma actuators becomes higher. At last, this paper demonstrated that simulation based on Laplace method could also be effective in the optimization of plasma actuators and the experiments results in this paper were also proved by this method too.