Characterization of spray formation from emulsions by pressure-swirl atomizers for spray drying

Tratnig, Andreas; Brenn, Günter; Strixner, Thomas; Fankhauser, Péter; Laubacher, Nina; Stranzinger, M.

doi:10.1016/j.jfoodeng.2009.04.015

Cited by 22 publications

(9 citation statements)

References 21 publications

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“…Numerous studies, both fundamental [20][21][22][23] and experimental [24][25][26][27][28][29], have shown that altering fluid properties such as surface tension, viscosity and specific gravity can affect both the spray breakup process and the spray cone angle, which in turn can affect the droplet size and velocity distributions. Since glycerol/water mixtures are inherently unstable, even minor changes in the spray characteristics can impact the ignition and stability of such systems.…”

Section: Preferential Vaporization Of Wet Fuelsmentioning

confidence: 99%

Spray breakup and structure of spray flames for low-volatility wet fuels

Madero

Axelbaum

2017

Combustion and Flame

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Studies of high-water-content fuels (a.k.a, wet fuels) have demonstrated that, under proper conditions, stable combustion can be achieved at very high water concentrations. Stable spray flames of wet fuels have been attained with fuel/water mixtures having stoichiometric adiabatic flame temperatures as low as 251 °C. In this study we investigate low-volatility wet fuels, using glycerol as the fuel, and ethanol as a stabilization additive. This study expands on previous work by determining the minimum amount of ethanol that needs to be added to a glycerol/water mixture to produce a stable flame and by investigating the spray dynamics and structure for these fuels, to delineate the mechanism of ignition and to understand how ethanol alters the vaporization behavior, droplet breakup, and spray dynamics. Detailed 2-D velocity, Sauter mean diameter (SMD), 2-D flux, and number concentration measurements were performed with a Phase Doppler Particle Analyzer (PDPA) in sprays of three fuel/water mixtures: a) 30% glycerol/70% water, b) 30% glycerol/10% ethanol/60% water, and c) the same mixture as b) but in a combusting spray. All percentages are by weight. Results show that the addition of ethanol to the glycerol/water mixture turns the hollow cone spray pattern into a narrow full cone pattern, leading to recirculation of fine droplets in the region just downstream of the nozzle, which is essential to ignition. The high concentration of fine droplets, along with the high vapor pressure and high activity coefficient of ethanol leads to extremely rapid vaporization of ethanol in the inner recirculation zone. The combustion of the ethanol raises the temperature in this region, while the swirling flow brings heat

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Section: Preferential Vaporization Of Wet Fuelsmentioning

confidence: 99%

Spray breakup and structure of spray flames for low-volatility wet fuels

Madero

Axelbaum

2017

Combustion and Flame

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“…The PDA system deduces the 2 measured quantities of particles penetrating the probe volume from the intensity of light scattered by the particles, which varies with time, and from a phase shift between pairs of scattered light signals, respectively. One important requirement to spherical liquid droplets when measuring their size with PDA is that they must exhibit homogeneous optical properties (Tratnig and others 2009; Liu and others 2010).…”

Section: Spray Technologymentioning

confidence: 99%

“…In all these applications, the physical properties of the used liquids (viscosity, surface tension, density, and so on) can be different and therefore the fluid behavior (drop generation) can be specific to each liquid. Thus, it is necessary to design different atomizers and more general spraying systems to respond to specific spray applications (Moita and others 2009; Tratnig and others 2009). Furthermore, final product quality, operating costs, and maintenance downtime are also parameters that affect spray nozzle selection, use, and application.…”

Section: Introductionmentioning

confidence: 99%

Atomizing Spray Systems for Application of Edible Coatings

Andrade

Skurtys

Osorio

2012

Comp Rev Food Sci Food Safe

173

120

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The use of edible coatings on fresh and processed food products as a means of extending shelf life by preventing or delaying spoilage, providing a partial barrier to moisture, oxygen, and carbon dioxide, improving the mechanical handling properties, and even as carriers of many functional ingredients, is rapidly growing. Edible coatings can be applied by different methods such as panning, fluidized bed, dipping, and spraying. This review presents and discusses some aspects of the application of edible coatings on food products using spraying, which is the most commonly used technique for applying food coatings and to obtain uniform layers.

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“…Both unit operations are an integrated process of atomization with either drying or chilling. Therefore, for understanding of spray-chilling or drying, atomization of emulsion has to be significantly studied in first place (Dubey et al, 2010(Dubey et al, , 2011bDumouchel, 2008;Tratnig et al, 2009;Walzel, 2010). Some authors (Bolszo et al, 2010;Broniarz-Press et al, 2009;Dubey et al, 2011b;Jayasundera et al, 2009) studied spraying of emulsion, where they investigated the influences of process conditions and viscosity of emulsion on the spray droplets as well as the spraying impact on the microstructure of emulsion.…”

Section: Introductionmentioning

confidence: 99%