A study of free-surface electrohydrodynamics

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5550886

Kaiser, K L

Free-surface electrohydrodynamics (EHD) is a complex phenomena that is difficult to describe, explain, and predict. An analytical and numerical study is performed to assist in the understanding of free-surface EHD. Rayleigh-type critical charge relationships are derived for spherical droplets of perfect and imperfect insulative liquids. Also, mathematical models and a simulator are developed to analyze free-surface EHD in two dimensions. Several configurations are investigated with the simulator. Analytical results indicate that if charge is uniformly dispersed throughout a spherical droplet of perfectly insulating fluid, breakup is possible. If the dielectric constant of the liquid is approximately equal to that of the surrounding air, the charge limit is approximately 10% less than that of a conducting fluid. If ionizable impurities are in the fluid but no transfer of charge occurs between the electrode and the fluid, breakup can still occur. If the liquid's dielectric constant is large, the total charge on the electrode is not much different from the Rayleigh number. A unique donor-cell method was developed to approximate the charge flow equation, properly conserving charge in each cell. A pseudo-surface charge method was also developed. The results were shown to be good for low curvature, simple geometries. Simulation results indicate that the effects of inertia can be substantial in the rise of dielectrophoretic fluid between two electrified plates. The initial stages of the radial breakup of a charged conducting fluid cylinder consisted of wave-like oscillations along the surface. The shape of an insulating jet from a nozzle was seen to be highly dependent on the electric field configuration.

• Research Organization: Purdue Univ., Indianapolis, IN (United States)
• OSTI ID: 5550886
• Country of Publication: United States
• Language: English

Related Subjects

665520* -- Other Methods of Direct Energy Conversion-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANALOG SYSTEMS
ANALYTICAL SOLUTION
CONFIGURATION
DROPLETS
ELECTRIC FIELDS
ELECTROHYDRODYNAMICS
FLUID MECHANICS
FUNCTIONAL MODELS
HYDRODYNAMICS
IMPURITIES
IONIZATION
MATHEMATICAL MODELS
MECHANICS
NOZZLES
NUMERICAL SOLUTION
PARTICLES
SIMULATORS
TWO-DIMENSIONAL CALCULATIONS
VARIATIONS
VISCOSITY