Ionic Wind Induced by Elementary Needle-Ring Structure Under Varying Temperature-Humidity Conditions

Abstract

Ionic wind is an emerging technique for air supply and heat-transfer enhancement, but it is affected by the experimental temperature and humidity significantly. Current studies mainly focus on the discharge characteristics, whereas research on the coupling mechanism of discharge and ionic-wind output under varying temperature-humidity conditions is quite scarce. In this study, a needle-ring ionic wind generator is used to clarify the variations and their internal correlation mechanisms of the transient, volt-ampere, and wind-velocity output characteristics of discharging under the temperature and humidity effects. The results indicate humidity reduces the Trichel-pulse frequency and increases the amplitude and transition voltage of Trichel pulse to pulse-free glow. The vapor condensation on the emitter produces the opposite effect. The two factors are in constant competition with each other, affecting the discharging, but both cause the pulse amplitude non-uniformity to increase. Temperature plays a role in regulating the relative strength of effects of humidity and vapor condensation. The ionic wind velocity generally changes little at the beginning with increasing humidity and then gradually increases, and this increase rate decreases with the increase in temperature. This study can be a guide for designing ionic wind devices operating under varying ambient conditions.

Keywords: Corona discharge, Ionic wind, Needle-ring structure, Temperature, Humidity