Dual-pin electrohydrodynamic generator driven by alternating current

Abstract

We report a unique alternating current (AC) driven corona based air-flow generator using symmetrically arranged electrodes. Unlike the conventional configuration where one electrode generates charged ions moving towards the reference electrode, this configuration allows both negative and positive charges to simultaneously move away from the device and generate ion wind in parallel with the electrodes. In comparison with the direct current (DC) driven corona generator, the time oscillating AC field allows the device a better stabilization owing to the independence of ion wind strength from the inter-electrode spacing. Our results by both simulation and experiment showed that when the AC frequency exceeds a threshold value of 1100 Hz, the electric field at the electrode tips is determined dominantly by the charge cloud created in the previous half-cycle, resulting in stronger net electric field and thus stronger ion wind. In addition, the electrode separation in the AC driven corona based generator is less critical above the frequency threshold, yielding a more robust design with minimized susceptibility to manufacturing tolerances and impurities on the electrodes. Moreover, lower voltage levels of the AC driven system allow simpler and more economical design in the high voltage circuit of the AC generator.

Charge reduced nanoparticles by sub-kHz ac electrohydrodynamic atomization toward drug delivery applications

“…Because of the reversed electric field, this length scale should be smaller than that estimated for electrohydrodynamic ac ionic winds recombined in classical nozzle-ring configuration 25 , i.e., < ~ ( ⁄ ) 1 2 ⁄ ~ 30 mm, where 2 ~ 0.1 the dimensionless parameter for the ion recombination rates and ion screening, ~ 10 -4 m 2 /Vs the ion mobility, = 4.2 kV and = 450 Hz. Additionally, the frequency range from 50 Hz to 100 Hz in our work considered as the shifting regime from dc driven to ac driven spray is also reasonably smaller than reported for ac ion wind as ~ 1500 Hz 26 . Figure 4(a) shows the charge of the particle flow measured by an electrometer probe (3608 TSI) placed 200 mm downstream from the capillary tip for the experiment shown in Fig.…”

Pulse Current of Multi-Needle Negative Corona Discharge and Its Electromagnetic Radiation Characteristics

“…Corona discharge, which is a relatively low-energy discharge process, occurs only in a strong electric field near a electrode with small radius of curvature [1] is a common discharge phenomenon in plasma generator [2], ozone generator [3], electrostatic precipitator [4], electrostatic printing, electrostatic charge of aerosol particles [5], high voltage transmission lines [6], and charged aircraft [7]. Corona discharge usually performs simultaneously in a multi-needle (multi-point) format [8][9][10].…”

Simultaneous Generation and Delivery of Neutral Polymeric Aerosol by Electro-Hydrodynamic Nebulizer

“…Furthermore, the momentum accumulated in the corona discharge is used to propell droplets forward to a desired target [10]. Compared with the previous systems where multi-actuators are activated by different power sources, the new approach not only saves energy due to using a single power source, but also enables effective droplet neutralization in a free space [11]. This approach possesses great potential for practical uses such as respiratory drug delivery or cell treatment.…”