Influence of space charge on the scale-up of multiplexed electrosprays

Deng, Weiwei; Gomez, Alessandro

doi:10.1016/j.jaerosci.2007.08.005

Cited by 86 publications

(60 citation statements)

References 18 publications

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“…Thus an out-scaling rather than up-scaling is needed for boosting the number of injection ports. There have been many ef forts reported on the out-scaling of EHDA including the use of an array of capillaries, an array of holes in combination with nonwetting material, serrations, grooves, multijet mode operation, and MEMS-based manufacturing as summarized by Deng and Gomez (2007). Increasing the number of capillary nozzles seems to be a simple and effective way of increasing the number of droplets.…”

Section: Electrohydrodynamic Atomizationmentioning

confidence: 99%

Generation and Sizing of Particles for Aerosol-Based Nanotechnology

Biskos

Vons

Yurteri

et al. 2008

KONA

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Section: Electrohydrodynamic Atomizationmentioning

confidence: 99%

Generation and Sizing of Particles for Aerosol-Based Nanotechnology

Biskos

Vons

Yurteri

et al. 2008

KONA

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“…The presence of satellite droplets in an EHDA process has also been reported. [18][19][20][21] To scale up the throughput of EHDA based atomisers, multiple nozzle systems have been developed. [22][23][24][25] However, the scale-up of EHDA-based spray dryers has been impeded due to the complexity of the electrostatic field arrangements applied to multiple jets, the specific requirements for the liquid properties and the relatively high cost to generate uniform droplets.…”

Section: Introductionmentioning

confidence: 99%

Optimizing the primary particle size distributions of pressurized metered dose inhalers by using inkjet spray drying for targeting desired regions of the lungs

Ehtezazi

Davies

Seton

et al. 2013

Drug Development and Industrial Pharmacy

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Optimizing the primary particle size distributions of pressurized metered dose inhalers by using inkjet spray drying for targeting desired regions of the lungs http://researchonline.ljmu.ac.uk/625/ Article LJMU has developed LJMU Research Online for users to access the research output of the University more effectively. Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Users may download and/or print one copy of any article(s) in LJMU Research Online to facilitate their private study or for non-commercial research. You may not engage in further distribution of the material or use it for any profit-making activities or any commercial gain. LJMU Research OnlineThe version presented here may differ from the published version or from the version of the record. Please see the repository URL above for details on accessing the published version and note that access may require a subscription. AbstractConventional suspension pressurised metered dose inhalers (pMDIs) suffer not only from delivering small amounts of a drug to the lungs, but also the inhaled dose scatters all over the lung regions. This results in much less of the desired dose being delivered to regions of the lungs. This study aimed to improve the aerosol performance of suspension pMDIs by producing primary particles with narrow size distributions. Inkjet spray drying was used to produce respirable particles of salbutamol sulphate. The Next Generation Impactor (NGI) was used to determine the aerosol particle size distribution and fine particle fraction (FPF).Furthermore, oropharyngeal models were used with the NGI to compare the aerosol performances of a pMDI with monodisperse primary particles and a conventional pMDI.Monodisperse primary particles in pMDIs showed significantly narrower aerosol particle size distributions than pMDIs containing polydisperse primary particles. Monodisperse pMDIs showed aerosol deposition on a single stage of the NGI as high as 41.75±5.76%, while this was 29.37±6.79% for a polydisperse pMDI. Narrow size distribution was crucial to achieve a high FPF (49.31±8.16%) for primary particles greater than 2µm. Only small polydisperse primary particles with sizes such as 0.65±0.28µm achieved a high FPF with (68.94±6.22%) or without (53.95±4.59%) a spacer. Oropharyngeal models also indicated a narrower aerosol particle size distribution for a pMDI containing monodisperse primary particles compared to a conventional pMDI. It is concluded that, pMDIs formulated with monodisperse primary particles show higher FPFs that may target desired regions of the lungs more effectively than polydisperse pMDIs.

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“…Additional Lagrangian simulations of sprays of charged droplets have been carried out by Wilhelm, Madler & Pratsinis (2003), who included the effect of the evaporation of the droplets in the surrounding gas; Oh, Kim & Kim (2008), who simulated the interaction of the sprays that issue from two sources in tandem; and Deng & Gomez (2007), who investigated the sprays beyond the extractor electrode of a multiplexed source and the conditions leading to path reversal and fly back of the satellite droplets toward the extractor. These authors also proposed simplified models of the space charge induced field, while Yang et al (2012) carried out massively parallel computations of multiplexed electrosprays.…”

Section: Introductionmentioning

confidence: 99%

Multifluid Eulerian model of an electrospray in a host gas

Higuera

2013

J. Fluid Mech.

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An Eulerian multifluid model is used to describe the evolution of an electrospray plume and the flow induced in the surrounding gas by the drag of the electrically charged spray droplets in the space between an injection electrode containing the electrospray source and a collector electrode. The spray is driven by the voltage applied between the two electrodes. Numerical computations and order-of-magnitude estimates for a quiescent gas show that the droplets begin to fly back toward the injection electrode at a certain critical value of the flux of droplets in the spray, which depends very much on the electrical conditions at the injection electrode. As the flux is increased toward its critical value, the electric field induced by the charge of the droplets partially balances the field due to the applied voltage in the vicinity of the injection electrode, leading to a spray that rapidly broadens at a distance from its origin of the order of the stopping distance at which the droplets lose their initial momentum and the effect of their inertia becomes negligible. The axial component of the electric field first changes sign in this region, causing the fly back. The flow induced in the gas significantly changes this picture in the conditions of typical experiments. A gas plume is induced by the drag of the droplets whose entrainment makes the radius of the spray away from the injection electrode smaller than in a quiescent gas, and convects the droplets across the region of negative axial electric field that appears around the origin of the spray when the flux of droplets is increased. This suppresses fly back and allows much higher fluxes to be reached than are possible in a quiescent gas. The limit of large droplet-to-gas mass ratio is discussed. Migration of satellite droplets to the shroud of the spray is reproduced by the Eulerian model, but this process is also affected by the motion of the gas. The gas flow preferentially pushes satellite droplets from the shroud to the core of the spray when the effect of the inertia of the droplets becomes negligible, and thus opposes the well-established electrostatic/inertial mechanism of segregation and may end up concentrating satellite droplets in an intermediate radial region of the spray.

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Influence of space charge on the scale-up of multiplexed electrosprays

Cited by 86 publications

References 18 publications

Generation and Sizing of Particles for Aerosol-Based Nanotechnology

Generation and Sizing of Particles for Aerosol-Based Nanotechnology

Optimizing the primary particle size distributions of pressurized metered dose inhalers by using inkjet spray drying for targeting desired regions of the lungs

Multifluid Eulerian model of an electrospray in a host gas

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