Optical Characterization of Ionic Wind Field by Means of Laser-Induced Phosphorescence

Flow velocity measurement of an ionic wind field with DC corona discharges in a needle-plate electrode system is experimentally investigated. A laser-induced phosphorescence phenomenon of vapor-phase biacetyl tracer is applied to identify the ionic wind velocity. The phosphorescence phenomenon is used as a molecular tagging approach for gas-phase flow visualization because a lifetime of the phosphorescence emission is much longer than the fluorescence emission. The visualization image shows a time-depended phosphorescence emission pattern blown away by the ionic wind. An image analysis for the luminescence pattern, which is captured with an elapsing time from the pulsed laser excitation, is enabled us to quantitatively characterize the ionic wind velocity. This paper presents the experimentally obtained visualization images of ionic wind movements, and describes the velocity identification on the phosphorescence image analysis.