Influencing Factors of Flow Field of Ionic Wind Induced by Corona Discharge in a Multi-Needle-to-Net Electrode Structure Under Direct-Current Voltage

The morphologies and velocity of ionic wind induced by direct-current (DC) corona discharge were experimentally measured. DC voltage was applied to short air gaps of high-voltage electrode-needle electrode and grounding electrode-net electrode to generate coronas, so as to allow the generation of ionic wind induced by corona discharge. The purpose of the study is to optimise the multi-needle-to-net electrode structure to improve the velocity of the ionic wind and keep it in a relatively stable state. For this purpose, the influences of various parameters on the velocity of the ionic wind were explored. The research results showed that the side length of meshes and the distribution mode of needles significantly affected the velocity of the ionic wind. The maximum velocity of the ionic wind, when the side length of meshes was 0.85 mm was 3 and 1.28 times those when the side lengths of the meshes were 2 and 0.425 mm, respectively. This indicated that there was an optimal side length that can maximise the velocity of the ionic wind. Increasing the number of needles and optimising the distribution mode of needles can effectively improve the velocity, that is, the improvement of the number and distribution uniformity of needles was conducive to increase the velocity of the ionic wind. Increasing the voltage amplitude can increase the velocity of the ionic wind, however, it was possible that noise was significant and in this case, the corresponding voltage cannot be considered as the working voltage of the ionic wind generator.