| As far back as 1709, under certain conditions, air flow was observed in the presence of high voltage. This phenomenon is an example of electrohydrodynamic flow. The presence of high voltage, on the order of thousands to tens of thousands of volts, along with one electrode of high curvature (sharp) and another electrode without sharp edges, will support an ionization cascade given an initial, natural ionization event. Under the right conditions, this will result in a sufficient number of ions to move a measurable amount of air due to momentum transfer between the ions and the neutral gas molecules. The current study investigated the efficiency and air flow enhancements of a small, simple ionic air moving device that consisted of needles and a 25 mm diameter cylinder. It was found that there was an optimal cylinder length, needle distance, polarity, and voltage for both air flow and efficiency, and it was shown that increasing the number of needles, and therefore ionization sites increased air flow and efficiency. Most importantly, perhaps, was the discovery that the predominant academic literature measured and reported efficiency differently than industry, giving the impression that ionic air flow devices were far inferior in terms of efficiency to conventional fans and blowers. The current work has shown that application of industry standard techniques and methodologies has resulted in a more favorable comparison to conventional air moving devices, and has also revealed that the efficiency of ionic devices shows great sensitivity to the parameters investigated in this work. |
