Comparison of Initiation and Temporal Evolution of Positive and Negative Ionic Wind Under Needle-to-Plate Electrode

Considerable research efforts have been devoted to the generation, characterization, and optimization of ionic wind produced by corona discharge. The current article tries to explain the mechanism that causes the different behaviors observed in negative and positive dc corona ionic wind. The steady-state and the transient state ionic wind produced by both polarities are studied through particle image velocimetry (PIV) technology. The results show that at transient state, a series of mushroom-like jets are produced in negative corona discharge ionic wind due to the effect of Trichel pulse. These jets merge with each other and combine momentum to form the wide structure at steady state. In comparison, the positive corona discharge current has no pulse, and the ionic wind has only one “I-shape” wave head during the initiation process. The dynamics of the jets is studied in detail. The formation of the jet series in negative corona, or single jet in the case of positive corona, is believed to play a key role in the generation of ionic wind.