Understanding Electrohydrodynamic Flow Using Particle Image Velocimetry in Alternating Current Corona Discharge Systems

Abstract

Abstract. Electrohydrodynamic (EHD) pumping induced by corona discharge under high-voltage sinusoidal alternating current (AC) presents unique challenges. These challenges include alternating electric fields from polarity reversals, periodic ionic flow changes, and repeated overcoming of the corona inception threshold, leading to complex fluid behavior. This study investigates the influence of input frequency on the performance of an AC corona discharge-induced EHD pump using particle image velocimetry (PIV). Experiments were conducted with silicone oils of varying viscosities (50 and 100 cSt) to evaluate the fluid behavior under a wide range of frequencies (0.01 Hz–10 Hz). The results demonstrate a frequency-dependent transition in oscillatory behavior, with fluids oscillating at twice the input frequency within lower ranges before aligning with the input frequency at higher ranges. Oscillation amplitudes peaked at 2 Hz and 1 Hz AC voltages for the 50 cSt and 100 cSt silicon oils, respectively, with higher frequencies showing decayed amplitudes due to viscous damping. Fourier analysis further revealed multi-harmonic behaviors, underscoring the system's nonlinear dynamics. This research highlights critical operational insights, including the optimal input frequency ranges for maximizing fluid oscillation amplitudes. By addressing the intricate interplay of ionization dynamics, fluid properties, and input frequency, this study provides a foundation for designing advanced EHD pumps tailored to precise applications. These findings have broad implications for microfluidics, thermal management, and biomedical engineering, offering a pathway to develop contactless, energy-efficient, versatile, and high-performance EHD systems under AC voltage conditions.