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Title:Field Injection Electrostatic Spraying of Liquid Hydrogen
Author(s):Woosley, James Patrick
Department / Program:Electrical Engineering
Discipline:Electrical Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Engineering, Electronics and Electrical
Abstract:Uniform charged liquid hydrogen drops have been produced using two different generating techniques. These two techniques are Rayleigh's method of uniform droplet production in conjunction with field injection charging and field injection electrostatic spraying.
The first method consists of applying a pressure drop across a glass capillary (nozzle) and thereby forming a smooth jet of liquid hydrogen. An acoustic wave of sufficient amplitude is then applied to the jet, which results in uniform drops at a frequency equal to the frequency of the acoustic wave. Charge is then injected into the jet through field ionization. This is accomplished by applying a high potential to a very sharp tungsten needle which protrudes slightly out of the nozzle. The end result is the formation of uniform charged liquid hydrogen drops.
The second method consists of forming a liquid hemisphere of hydrogen at the end of a glass nozzle. A small pressure drop across the nozzle results in a constant volume flow rate of liquid through the nozzle. A large drop forms and drips off, thus, this mode is known as the dripping mode. Field ionizaton is again utilized to inject charge into the liquid. As the charge on the surface increases, electrostatic forces eventually overcome surface tension forces and, consequently, the unstable surface throws off a charged drop. This mode is known as the dribbling mode.
As the injection current is increased, the drops become smaller and their frequency increases. Eventually, a charged jet forms which then breaks up into small uniform charged drops. This second mode is known as the jet mode. This jet is formed purely by electrical forces, whereas in the first method the jet was formed by mechanical forces.
An experimental apparatus was built which used both methods to produce the uniform charged drops of liquid hydrogen. Following the experimental work, a theory was developed which would predict the size and charge of the drops.
A qualitative theory was derived which explains field injection electrostatic spraying in the dribbling mode. Another theory was revised and now it quantitatively describes field injection electrostatic spraying in the jet mode.
Issue Date:1981
Description:103 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1981.
Other Identifier(s):(UMI)AAI8203642
Date Available in IDEALS:2014-12-15
Date Deposited:1981

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