Electrospray of 1-Butyl-3-Methylimidazolium Dicyanamide Under Variable Flow Rate Operations

Miller, Shawn W.; Prince, Benjamin D.; Bemish, Raymond J.; Rovey, Joshua L.

doi:10.2514/1.b35170

Cited by 27 publications

(34 citation statements)

References 30 publications

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“…The electrospray source in both setups was identical and has been described in previous works. [10,11] The source was simply the pairing of an extractor plate with a 1.5 mm diameter aperture and a conductive emitter (i.e. metalcoated fused-silica capillary at 50 µm diameter) set approximately 1.5 mm apart.…”

Section: Methodsmentioning

confidence: 99%

“…We have previously reported on the effects of volumetric flow rate on the emitted ion species from a capillary-style emitter employing the ionic liquid BMI-DCA (1-butyl-3methylimidazolium dicyanamide). [10,11] At the lowest flow rates sampled, the smallest ion species appeared to be the most intense as measured through quadrupole mass spectrometry with an upper m/q range of 1,000 amu/q. As the flow rate was increased, the presence of larger ion clusters such as the n = 3, 4, and 5 cations (i.e.…”

Section: Introductionmentioning

confidence: 97%

“…Previous investigations of needle and capillary electrospray emitters at the Air Force Research Laboratory using quadrupole mass spectrometry coupled with retarding potential analysis (RPA) have noted that the presence of large mass-to-charge droplets near the center emission axis have also been correlated with reduced kinetic energies of the ions, as compared to the bias potentials applied to the emitters. [10,11,13] These losses are typically termed "ohmic losses" and are understood to occur as a result of jet extension from the Taylor cone structure. These losses impact the E American Institute of Aeronautics and Astronautics thrust performance of the device through a reduction in the net acceleration of the ion, as compared to the theoretical maximum.…”

Section: Introductionmentioning

confidence: 99%

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Mass Spectrometry of Selected Ionic Liquids in Capillary Electrospray at Nanoliter Volumetric Flow Rates

Miller

Prince²,

Bemish³

et al. 2016

52nd AIAA/SAE/ASEE Joint Propulsion Conference

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Capillary-based electrospray thrusters allow user-enabled control of the volumetric flow rate of the propellant. This control, coupled with mass spectrometry techniques spanning a large mass-to-charge range, enables elucidation of the composition of the electrospray beam and through further analyses, a better understanding of the physics occurring at the liquid/vacuum interface. In this work, mass spectra of selected ionic liquids electrosprayed from a capillary emitter are measured, using time-of-flight mass spectrometry, over a wide range of volumetric flow rates. The time-of-flight mass spectrometer enables simultaneous acquisition over a mass-to-charge range of 20 amu/q to ~500,000 amu/q in a single pulse cycle. Additionally, the use of orthogonal extraction enables direct determination of the kinetic energies of ions present in the electrosprayed beam. The presented data reveal a complex emission process occurring for ionic liquid capillary-based electrospray at nanoliter volumetric flow rates. The electrospray beam mass-to-charge composition includes a sequence of singly-charged ions and doubly-charged ions at nearly all sampled flow rates for all electrosprayed ionic liquids. In addition to the small ion-clusters, two Maxwell-Boltzmann distributions from approximately 10,000 amu/q to 500,000 amu/q exist in the spectra each with mass-to-charge distribution sensitive to the volumetric flow rate. The volumetric flow rate dependence of the largest charge-to-mass ratio droplets appears to be consistent with previously measured scaling laws, although exhibiting a wide mass-to-charge distribution. The flow rate dependence of the lower mass-to-charge distribution is more complex and is discussed in some detail. Measurement of the time-of-flight mass spectrum for a number of different ion kinetic energy defects over a number of different volumetric flow rates results in a more thorough understanding of kinetic energy losses experienced in the jet structure of the Taylor cone, with direct impacts to the thrust performance of these types of devices. The appearance of these ions and distributions alter the thought on the emission mechanism at work in the electrospray system. No longer is electrospray defined and easily explained by the Iribarne emission mechanism and droplet generation by the Rayleigh instability.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Mass Spectrometry of Selected Ionic Liquids in Capillary Electrospray at Nanoliter Volumetric Flow Rates

Miller

Prince²,

Bemish³

et al. 2016

52nd AIAA/SAE/ASEE Joint Propulsion Conference

Self Cite

View full text Add to dashboard Cite

show abstract

“…Miller et al reported absolute emission currents of a 1-butyl-3-methylimidazolium dicyanamide (BMIM-DCA) capillary electrospray at 589, 772, and 1032 nA for flowrates 0.46, 0.82, 1.29 nl/s. 7 The increase in BMIM-DCA emission current compared to EMIM-NTf2 at similar flowrates is the result of the increase in conductivity, from 0.92 to 1.052 S/m, surface tension, from 35.7 mN/m to 48.6 mN/m, and a decrease in electrical permittivity, from 12.3 to 11.3. The ILFF solutions used in Exp-1 and Exp-2 also have different fluid and electrical properties than its neat IL carrier fluid.…”

Section: A Effects Of Nanoparticle Concentrationmentioning

confidence: 94%

The effects of magnetic surface stress on electrospray of an ionic liquid ferrofluid

Terhune¹,

King²,

Prince³

et al. 2016

52nd AIAA/SAE/ASEE Joint Propulsion Conference

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Four solutions of an ionic liquid ferrofluid (ILFF) using 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-NTf2) as the carrier liquid were emitted from a capillary electrospray source and its beam was measured using a time-of-flight mass spectrometer (TOF-MS) and a downstream stack of Faraday plates. The solutions had 3.04, 5.98, 8.80, and 14.15 wt% iron-oxide nanoparticles making them susceptible to magnetic fields. A Helmholtz coil was used to impose a magnetic stress onto the electrospray source. The addition of nanoparticles to neat IL increased viscosity, and decreased conductivity and surface tension of the fluid. The emission current followed the proportionality Ĩ Q K 2  = Liquid viscosity P  = Pressure drop through capillary tube = Particle charge Q = Volumetric flowrate min Q = Minimum volumetric flowrate c r = Capillary tube radius ℎ = Time-of-flight u = Particle velocity V = Voltage

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“…[93,[100][101][102][103]. Liquid metals like cesium, gallium and indium have also been used as propellants due to their high atomic mass and a low ionization potential [104].…”

Section: Design Considerations and Technologiesmentioning

confidence: 99%

An Overview of Cube-Satellite Propulsion Technologies and Trends

2017

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CubeSats provide a cost effective means to perform scientific and technological studies in space. Due to their affordability, CubeSat technologies have been diversely studied and developed by educational institutions, companies and space organizations all over the world. The CubeSat technology that is surveyed in this paper is the propulsion system. A propulsion system is the primary mobility device of a spacecraft and helps with orbit modifications and attitude control. This paper provides an overview of micro-propulsion technologies that have been developed or are currently being developed for CubeSats. Some of the micro-propulsion technologies listed have also flown as secondary propulsion systems on larger spacecraft. Operating principles and key design considerations for each class of propulsion system are outlined. Finally, the performance factors of micro-propulsion systems have been summarized in terms of: first, a comparison of thrust and specific impulse for all propulsion systems; second, a comparison of power and specific impulse, as also thrust-to-power ratio and specific impulse for electric propulsion systems.

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Electrospray of 1-Butyl-3-Methylimidazolium Dicyanamide Under Variable Flow Rate Operations

Abstract: This report is published in the interest of scientific and technical information exchange, and its publication does not constitute the Government's approval or disapproval of its ideas or findings.

Cited by 27 publications

References 30 publications

Mass Spectrometry of Selected Ionic Liquids in Capillary Electrospray at Nanoliter Volumetric Flow Rates

Mass Spectrometry of Selected Ionic Liquids in Capillary Electrospray at Nanoliter Volumetric Flow Rates

The effects of magnetic surface stress on electrospray of an ionic liquid ferrofluid

An Overview of Cube-Satellite Propulsion Technologies and Trends

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