Master of Science, The Ohio State University, 2008, Graduate School

Committee: Not Provided (Other) Subjects:

Doctor of Philosophy, University of Toledo, 2021, Engineering

Electrohydrodynamic (EHD) found a lot of attention in the scientific community because of its low energy and flexibility in addressing different challenges. The first chapter of this dissertation explains the history of using EHD to manipulate, separation and emulsion formation, and also talks about the theory and mechanism of gaseous discharge. The second chapter of this dissertation presents the results of experimental observations of the EHD flow induced in bulk dielectric liquid layers using corona discharge. The governing liquid properties for the deformations are discussed, indicating the vital role of surface tension and viscosity. Critical voltages at which rapid transformation of the liquid's deformation occurs are identified and discussed. The liquid layer thickness is shown to be a dominant parameter in the efficacy of such proposed pump designs. Chapter third discusses an experimental approach to study the effects of a contactless method on electrocoalescence of water in oil (W/O) emulsion. A positive corona discharge is utilized to create a nonuniform electric field for the coalescence of water droplets ranging from nano to macro sizes in oil mediums. Two approaches are employed in this chapter; qualitative analysis conducted by visually studying coalescence patterns in videos captured with a high-speed camera, and a quantitative analysis based on calculations obtained from dynamic light scattering (DLS) measurements. From the behavior of the water droplets under the electric field, it is observed that dipole-dipole interaction (DDI), migratory coalescence (electrophoresis (EP)), and dielectrophoresis (DEP) have major roles in promoting the coalescence events. Chapter fourth investigates the impacts of non-uniform and pulsed DC electric fields on the coalescence of water droplets inside an oil medium. The operating process parameters were experimentally calibrated and optimized to increase the effectiveness and energy consumption efficiency of the coa (open full item for complete abstract)

Committee: Hossein Sojoudi (Committee Chair); Abbas Semnani (Committee Member); Richard G. Molyet (Committee Co-Chair); Mohammed Niamat (Committee Member); Yakov Lapitsky (Committee Member) Subjects: Chemical Engineering; Electrical Engineering; Engineering; Fluid Dynamics; Petroleum Production; Physical Chemistry; Plasma Physics

Doctor of Philosophy, The Ohio State University, 1979, Graduate School

Committee: Not Provided (Other) Subjects: Engineering

Doctor of Philosophy, Case Western Reserve University, 2013, EECS - Electrical Engineering

This work demonstrates an innovative microfabricated air cooling technology that employs an electrohydrodynamic (EHD) corona discharge or ionic wind pump that has the potential to meet industry requirements as a next generation solution for thermal management applications. A single ionic wind pump element consists of two parallel collecting electrodes between which a single emitting tip is positioned. A grid structure on the collector electrodes enhances the overall heat transfer coefficient and facilitates an IC compatible and batch process. The main purpose of the work presented here is thus to investigate whether an optimized ionic wind pump employed in an array configuration might exhibit performance comparable to a conventional CPU fan. The manufacturing procedure developed for the device uses a glass wafer, a single mask-based photolithography process, a low cost copper-based electroplating method, and explores the effect of employing a palladium coating on the device. Various design configurations and optimization processes were explored and modeled computationally to investigate their influence on the cooling phenomenon. The optimized single element device provides a convection heat transfer coefficient of up to 3200 W/m2-K and a COP of up to 46.7 (a maximum COP of 51.5 exhibited by the 6-element array) exhibiting an overall area of 5.35 mm x 3.61 mm, an emitter-to-collector gap of 500 ¿¿m, and an emitter radius curvature of 12.5 ¿¿m. When compared with other ionic wind pumps, the device developed for this work is superior in terms of heat transfer coefficient and COP. However, the overall performance of the array does not compare favorably to a conventional CPU fan except in terms of COP. Additionally, the lifetime experiments conducted demonstrate that additional work may be required to extend the operation of the device, and some form of non-porous coating may be required to protect the underlying copper material. Nonetheless, the device described herein (open full item for complete abstract)

Committee: Alexis Abramson PhD (Advisor); Norman Tien PhD (Committee Member); Christian Zorman PhD (Committee Member); Jaikrishnan Kadambi PhD (Committee Member) Subjects: Design; Electrical Engineering; Electromagnetics; Energy; Engineering; Experiments; Fluid Dynamics; Materials Science; Mechanical Engineering; Physics; Plasma Physics; Solid State Physics; Systems Design; Theoretical Physics