Characterization of ionic wind velocity

When a strong electric field is generated between a sharp object at high voltage and a grounded electrode in a gas medium, a corona is formed near the tip of the sharp object and, as a result, the gas medium is set in motion. The current study reports on the flow behavior of a single-stage ion wind generator with and without a nozzle attached. Ion winds have rarely been measured quantitatively because traditional velocimeters (e.g., pitot tubes) have difficulty detecting their low flow speeds. In addition, seed-based measurement techniques (e.g., particle image velocimetry) are complicated by the possibility of electrical charging of the flow seed. In the present study, therefore, we obtain the velocity profile at the exit plane of an enclosed pinto-ring ion wind generator using two techniques to help validate our results: (1) particle image velocimetry downstream of the charge containing region and (2) hot wire anemometry. The velocity profiles indicate consistently that a pin-to-ring ion wind generator produces a velocity field with a deficit at its core. The velocities are sensitive to electrode alignment and, consequently, producing symmetric profiles is difficult. The results also show that only a slight increase in velocity can be achieved by placing a converging nozzle downstream of the electrodes. (c) 2005 Elsevier B.V. All rights reserved.