Session: Research Posters

Paper Number: 163800

Understanding Electrohydrodynamic Flow Using Particle Image Velocimetry (Piv) in Ac Corona Discharge Systems 

Electrohydrodynamic (EHD) pumping induced via corona discharge with alternating current (AC) voltage presents unique challenges, including alternating electric fields, periodic ionic flow reversals, and repeated overcoming of the corona inception threshold, leading to complex and unpredictable 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). The research focuses on how varying AC voltage frequencies impact the fluid motion characteristics of silicone oils with different viscosities (50 and 100 cSt). Experiments were conducted under a broad range of frequencies (0.01 Hz to 10 Hz) to analyze flow behavior, oscillatory patterns, and amplitude variations.  

The results reveal a frequency-dependent transition in oscillatory behavior, where at lower input frequencies, fluid motion oscillates at twice the applied frequency due to alternating positive and negative corona discharge cycles. However, as the frequency increases beyond a threshold (2.5 Hz for 50 cSt oil and 2 Hz for 100 cSt oil), the oscillation frequency aligns with the input signal. The oscillation amplitude peaks at 2 Hz for 50 cSt oil and at 1 Hz for 100 cSt oil, followed by a gradual decay at higher frequencies due to increased viscous damping. Fourier Transform analysis of the velocity signals reveals strong multi-harmonic components at lower frequencies, highlighting the highly nonlinear nature of AC-driven EHD flows.  

The study further investigates the out-of-plane velocity fluctuations induced by the AC corona discharge, manifesting as surface sloshing motions in the confined geometry of the pump. This effect is more pronounced in the lower-viscosity (50 cSt) fluid due to its lower resistance to deformation, while the higher-viscosity (100 cSt) fluid exhibits a more stable response with attenuated oscillations. Cross-correlation analysis confirms the presence of a phase lag between different regions of the flow domain, emphasizing the importance of viscosity in determining flow stability and response to AC input signals. 

These findings have significant implications for the design and optimization of AC-driven EHD pumps, particularly in microfluidic systems, thermal management applications, and biomedical engineering. By systematically characterizing the effects of input frequency on fluid transport efficiency, this study provides critical insights for achieving controlled and energy-efficient pumping mechanisms. The observed nonlinearity and frequency-dependent behavior suggest that precise frequency tuning can be employed to enhance flow stability and transport performance. Future research should explore the influence of additional parameters, such as electrode geometry, voltage amplitude, and fluid dielectric properties, to further refine the operational efficiency of AC corona discharge-based EHD systems.  

Presenting Author: Hossein Sojoudi University of Toledo

Presenting Author Biography: Dr. Hossein Sojoudi earned his Ph.D. in Mechanical Engineering from the Georgia Institute of Technology and completed postgraduate studies in Chemical Engineering at the Massachusetts Institute of Technology. Throughout his career, he has received numerous accolades, including the President’s Award for Excellence in Creative and Scholarly Activity at the University of Toledo. He is the former CEO and Founder of Compressed Natural Gas (CNG) and holds several US patents in mitigation of atmospheric icing for technology he developed at MIT, before joining UToledo. He is the Founder and Director of the Interfacial Thermal-Fluid Engineering Lab, where his team investigates liquid-liquid and liquid-solid interactions at the micro/nanoscale to improve efficiency and reliability with applications in emulsification, water purification, oil and gas production, and ice mitigation. In recent years, his research has focused on developing corona discharge technologies for emulsification processes in the cosmetics, pharmaceuticals, and food industries.

Authors:

Priscilla Aprepary University of Toledo
Bilal Nizar Abdul Halim University of Toledo
Ehsan Khoshabkhtnejad University of Toledo
Omid Amili University of Toledo
Hossein Sojoudi University of Toledo