Trichel pulses and ionic wind in a tube-plate air gap

Abstract

Trichel pulses could be observed in negative corona that was typically generated in a needle-plate gas gap. In the present work, we studied the properties and discharge mechanism of the Trichel pulse produced by a tube-plate structure, and some distinguished features were observed by both modeling and experiments. A classic three-species fluid discharge model was adopted to study the discharge dynamics and coupling with a hydrodynamic model to solve for the induced flow field (ionic wind). The model was validated with experimental observations and measurement. Trichel pulses were observed in the tube-plane geometry, but with higher sustaining voltage (in the order of −10 kV), higher peak current (in the order of 10 mA), and lower repeating frequency (in the order of 10 kHz) than these in the corresponding needle-plate corona system (in the order of –1 kV, 1 mA, and 100 kHz, respectively). Due to the electrostatic force, the negative corona around the tube orifice would deflect outward. A strong perturbation to the neutral gas associated with the corona was observed in the experiment and predicted by simulation. Ambient air around the tube orifice would be inhaled into the tube and then exhausted from the other end with the velocity of about 1.9 m/s. Slightly temperature rise at the tube tip by about 40 K was predicted by the model. Effects of the voltage amplitude and the tube diameter were then parametrically discussed. Results in the present work might contribute to an extended understanding of discharge mechanism of Trichel pulses in negative corona.