Dissertation/Thesis Abstract

Ionic emission from Taylor cones
by Castro Reina, Sergio, Ph.D., Yale University, 2009, 163; 3362197
Abstract (Summary)

Electrified Taylor cones have been seen as an efficient way to generate thrust for space propulsion. Especially the pure ionic regime (PIR) combines a very high specific impulse (thrust per unit mass) and efficiency, which is very important to reduce fuel transportation costs.

The PIR has been primarily based on electrosprays of liquid metals [Swatik and Hendricks 1968, Swatik 1969]. However, emissions dominated by or containing exclusively ions have also been observed from nonmetallic purely ionic substances, initially sulfuric acid [Perel et al. 1969], and more recently room temperature molten salts referred to as ionic liquids (ILs) [Romero-Sanz et al. 2003].

The recent use of the liquid metal ion source (LMIS) with ILs, becoming this "new" source to be known as ionic liquid ion source (ILIS) [Lozano and Martinez-Sanchez 2005], has shown important differences on the emission from Taylor cones with the traditional hollow capillary. This new source seems to be more flexible than the capillary [Paulo, Sergio, carlos], although its low emission level (low thrust) is an important drawback from the space propulsion point of view.

Throughout the thesis I have studied some aspects of the ionic emission from ionic liquid Taylor cones and the influence of the properties of the liquids and the characteristic of source on the emission. I have unraveled the reason why ILIS emits such low currents (∼200 nA) and found a way to solve this problem increasing the current up to capillary levels (∼1000 nA) [Castro and Fernandez de la Mora 2009]. I have also tried to reduce ion evaporation while reducing the emitted droplet size in order to increase the thrust generated while keeping the efficiency relatively high and I have measured the energy of evaporation of several cations composing ionic liquids, mandatory step to understand ionic evaporation.

Indexing (document details)
Advisor: Mora, Juan Fernandez de la
Commitee:
School: Yale University
School Location: United States -- Connecticut
Source: DAI-B 70/06, Dissertation Abstracts International
Source Type: DISSERTATION
Subjects: Analytical chemistry, Aerospace engineering
Keywords: Electrospraying, Ionic emission, Ionic liquids, Taylor cones, Tungsten
Publication Number: 3362197
ISBN: 978-1-109-21143-6
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