Electrospray Propulsion Based on Emitters Microfabricated in Porous Metals

Legge, Robert S.; Lozano, Paulo

doi:10.2514/1.50037

Cited by 105 publications

(77 citation statements)

References 14 publications

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“…The potential benefits of ILIS include: i) the low surface tension of ILs leads to low operating voltages compared with LMIS, ii) ILs are liquid at room temperature and therefore may not require heating, iii) many ILs have negligible vapour pressure, enabling storage at vacuum, iv) positive and negative ion emissions can be sustained, enabling charge neutralization without a dedicated neutralizer, v) high specific impulses, in excess of 3000 s [16], and propulsive efficiencies nearing 90 % [8] and finally, vi) the low flow rates inherent can be accommodated through passive feeding alone [2,7,17]. The later feature could greatly reduce the mass, power and volume requirements of a thruster by obviating the need for pumps, valves and propellant pressurization systems.…”

Section: Introductionmentioning

confidence: 99%

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Comparing Direct and Indirect Thrust Measurements from Passively Fed Ionic Electrospray Thrusters

Courtney

Dandavino

Shea

2016

Journal of Propulsion and Power

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Highly ionic beams of several hundred μA per cm 2 have been measured from porous glass ionic liquid electrospray sources fabricated using a conventional mill. The thrust output from three prototype devices, two emitting the ionic liquid EMI-Im and one emitting EMI-BF 4, was measured directly using a precise balance. Thrusts up to 50 μN were measured when emitting EMI-Im in a bipolar, alternating potential configuration at less than 0.8 W input power and with propellant supplied from an internal reservoir. Measurements of mass spectra via Time of Flight spectrometry, angle resolved current distributions, ion fragmentation and energy deficits have been applied to accurately calculate thrust and mass flow rates indirectly from the same devices. For two of three cases, calculated and directly measured thrusts were in agreement to within a few μN at input powers from 0.1 W to 0.8 W . Emissions of EMI-BF4 are shown to yield nearly purely ionic beams supporting high propulsive efficiencies and specific impulses, ∼ 65 % and > 3200 s respectively at 0.5 W . Conversely, greater polydispersity was observed in EMI-Im emissions, contributing to reduced specific performance, ∼ 50 % propulsive efficiency and ∼ 1500 s specific impulse at 0.5 W .

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Section: Introductionmentioning

confidence: 99%

“…However, Ref. [16] presents the only instance of DTM from a passively fed ILIS known to the authors. That study confirmed that thrusts of ∼ 0.1 μN/μA can be achieved from arrays of ILIS and that these levels are close to those expected by extrapolation of indirect calculations based on individual emitter measurements.…”

Section: Introductionmentioning

confidence: 99%

Comparing Direct and Indirect Thrust Measurements from Passively Fed Ionic Electrospray Thrusters

Courtney

Dandavino

Shea

2016

Journal of Propulsion and Power

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“…6 For electrospray devices, indirect thrust measurement by time-of-flight mass spectrometry (ToF-MS) has been the most widely used method, but it requires a good knowledge of the beam composition. [6][7][8][9] Direct measurement of thrust has also been performed for some electrospray propulsion devices. 6,8,19 If an electrospray emitter emits a current I of particles with uniform kinetic energy qV em , the normal thrust on the device can be written as 6 where m 0 and q are mass and charge of a monomer emitted from the ionic liquid.…”

Section: Thrust Measurement From An Electrospray Devicementioning

confidence: 99%

“…[6][7][8][9] Direct measurement of thrust has also been performed for some electrospray propulsion devices. 6,8,19 If an electrospray emitter emits a current I of particles with uniform kinetic energy qV em , the normal thrust on the device can be written as 6 where m 0 and q are mass and charge of a monomer emitted from the ionic liquid. γ 0 is a factor that takes into account the emission of different charge species together and is obtained from ToF traces of the emission.…”

Section: Thrust Measurement From An Electrospray Devicementioning

confidence: 99%

“…1,2 Several miniature thruster technologies, such as, cold-gas thrusters, 1,3 electrospray propulsion using liquid metals 4 or ionic liquids, [5][6][7][8][9][10][11] micro resisojets, 12,13 and micro pulsed plasma thrusters 13 are under investigation as prospective candidates targeting stable thrusts in the range of a few µN to several hundred µN. Several thrust-stands have been reported over the last few years for measuring thrust from these microthrusters with sub-µN resolutions.…”

Section: Introductionmentioning

confidence: 99%

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A 10 nN resolution thrust-stand for micro-propulsion devices

Chakraborty

Courtney

Shea

2015

Review of Scientific Instruments

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We report on the development of a nano-Newton thrust-stand that can measure up to 100 µN thrust from different types of microthrusters with 10 nN resolution. The compact thrust-stand measures the impingement force of the particles emitted from a microthruster onto a suspended plate of size 45 mm × 45 mm and with a natural frequency over 50 Hz. Using a homodyne (lock-in) readout provides strong immunity to facility vibrations, which historically has been a major challenge for nano-Newton thrust-stands. A cold-gas thruster generating up to 50 µN thrust in air was first used to validate the thrust-stand. Better than 10 nN resolution and a minimum detectable thrust of 10 nN were achieved. Thrust from a miniature electrospray propulsion system generating up to 3 µN of thrust was measured with our thrust-stand in vacuum, and the thrust was compared with that computed from beam diagnostics, obtaining agreement within 50 nN to 150 nN. The 10 nN resolution obtained from this thrust-stand matches that from state-of-the-art nano-Newton thrust-stands, which measure thrust directly from the thruster by mounting it on a moving arm (but whose natural frequency is well below 1 Hz). The thrust-stand is the first of its kind to demonstrate less than 3 µN resolution by measuring the impingement force, making it capable of measuring thrust from different types of microthrusters, with the potential of easy upscaling for thrust measurement at much higher levels, simply by replacing the force sensor with other force sensors. C 2015 AIP Publishing LLC. [http://dx

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Shear‐Induced Macropore‐Infused Nanocomposite Emulsion Thermosets

Hasan

Patel

Gamboa

et al. 2022

Adv Materials Inter

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To create macropore‐infused nanocomposite emulsion thermosets (MINET), a mixing pathway is demonstrated in which a viscous fluid is kinetically trapped by high shear mixing of immiscible liquids, surfactant, and nanoparticles. The MINETs are prepared from common ingredients that are widely employed in industry, including epoxy resin, vegetable oil, epoxidized soybean oil, and different types of nanoparticles such as silica, activated carbon, alumina, and zinc oxide. MINETs prepared by the presented route are processed at ambient conditions and exhibit low shrinkage (<2%). Furthermore, they are suitable to form macro‐ to microscale structures with high precision and various controlled porosity. The interconnected porous architecture of MINET is even preserved in molded micrometer‐scale features and thus ensures mass transport through multiscale structures. In combination with standard microembossing or photolithography, the high throughput microfabrication of microstructured architectures with tunable pore sizes in a wide range (≈100 nm to ≈10 µm) is possible. As one application example, the parallel production of multiplexed electrospray emitters is demonstrated.

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Electrospray Propulsion Based on Emitters Microfabricated in Porous Metals

Cited by 105 publications

References 14 publications

Comparing Direct and Indirect Thrust Measurements from Passively Fed Ionic Electrospray Thrusters

Comparing Direct and Indirect Thrust Measurements from Passively Fed Ionic Electrospray Thrusters

A 10 nN resolution thrust-stand for micro-propulsion devices

Shear‐Induced Macropore‐Infused Nanocomposite Emulsion Thermosets

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