Numerical and Experimental Study of Electrohydrodynamic Flow For A Pin-to-Plane Electrostatic Atomizer

This dissertation investigates electrohydrodynamic (EHD) flows in pin-to-plane electrostatic atomizers through numerical, analytical, and experimental approaches. The research addresses challenges in optimizing electrostatic atomizer designs for charge injection for use in industrial applications. The study begins with a numerical evaluation of electric field and potential distributions for various geometric configurations, highlighting the dominant role of sharp curvatures and relative proximity of electrode structures to the counter electrode. Analytical solutions for a hyperbolic paraboloid geometry model further explores the interplay between normal and tangential electric field components. It reveals the dominance of the normal electric field components, despite the curvature inducing tangential field components; diminishing the significance of the tangential component as a potential driving mechanism for EHD flows. A comprehensive numerical parametric analysis examines the effects Reynolds number, mobility, charge injection level, and charge injection area on flow structures; identifying conditions that may lead to unsteady flow patterns. Response surface methodology and multivariate statistical analysis quantify parameter interdependencies and their influence on charge profiles, peak velocities, and impingement pressures. Experimentally, a multi-scale, dual-domain Particle Image Velocimetry (PIV) study was conducted to capture high-resolution local and bulk flow dynamics at applied voltages ranging from 4 to 12 kV. The results reveal correlations between applied potential, flow velocity, and emergent flow structures, including a novel pattern of interlocking vortices. This work advances the understanding of EHD phenomena in pin-to-plane configurations and provides actionable guidelines for optimizing electrostatic atomizer designs. The findings and methodologies contribute to the development of more efficient and versatile systems tailored to diverse industrial needs.