Numerical study of the effect of gas-to-liquid ratio on the internal and external flows of effervescent atomizers

Mousavi, Milad; Dolatabadi, Ali

doi:10.1139/tcsme-2017-0125

Cited by 6 publications

(3 citation statements)

References 20 publications

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“…The internal flow pattern was noted to affect the fluctuation characteristics of the spray. Mousavi and Dolatabadi 16 conducted 3d large-eddy simulations of both internal and external flow in an effervescent atomizer and demonstrated decreasing breakup lengths and increasing spray cone angles with increasing GLR. Also other studies on atomizer internal flow have been carried out in 2d [17][18][19] and 3d 20 .…”

Section: Please Cite This Article As Doi:101063/50028963mentioning

confidence: 99%

Numerical study of bubbly flow in a swirl atomizer

et al. 2020

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In the present work, we extend our previous research on swirl nozzles by introducing bubbles at the nozzle inlet. A large-scale hollow cone pressure-swirl atomizer is studied using scale-resolving simulations. The present flow conditions target a Reynolds number range of 600 ≤ Re ≤ 910 and gas-to-total volumetric flow rate ratios between 0.07 ≤ β ≤ 0.33 with β = 0 as an experimental and computational reference. The computational setup has relevance to high-viscosity bio-fuel injection processes. Flow rate ratio and bubble diameter sweeps are carried out to study their effect on the inner-nozzle flow and the liquid film characteristics outside the nozzle. The present flow system is shown to pose highly versatile physics including bubble coalescence, bubble-vortex interaction, and faster liquid film destabilization relative to β = 0 case. The main results are as follows. (1) β is found to have a significant effect on the bimodal bubble volume probability density function (PDF) inside the swirl chamber. Also, the total resolved interfacial area of the near-orifice liquid film increases with β. (2) At representative value of β = 0.2, the exact bubble size at the inlet is observed to have only a minor effect on the swirl chamber flow and liquid film characteristics. (3) The bubble-free (β = 0) and bubbly (β > 0) flows differ in terms of effective gas core diameter, core intermittency features, and spray uniformity. The quantitative analysis implies that bubble inclusion at the inlet affects global liquid film characteristics with relevance to atomization.

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Section: Please Cite This Article As Doi:101063/50028963mentioning

confidence: 99%

Numerical study of bubbly flow in a swirl atomizer

et al. 2020

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“…While there are some computational studies of pneumatic internal-mixing models, most of them modelled only waterair mixtures or did very limited experimental validation of the model [5,6]. Only Wittner et al [7] focused on the ACLR nozzle design.…”

Section: Introductionmentioning

confidence: 99%

Experimental Analysis and CFD Modelling of the Flow Conditions inside an Air-Core-Liquid-Ring Atomizer

Ballesteros¹,

Gaukel²

2022

International Conference on Fluid Flow, Heat and Mass Transfer

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The Air-Core-Liquid-Ring (ACLR) atomization is an innovative internal-mixing pneumatic atomization technique, suitable for energy-efficient spray drying because of its ability to handle highly viscous liquid feeds with high solid contents. However, pneumatic atomizers such as the ACLR can suffer from unstable internal flow conditions, which may lead to a wide variation in the droplet diameter obtained. Therefore, the internal flow conditions of an ACLR-atomizer prototype needed to be studied and comprehended. With that in mind, a computational fluid dynamic (CFD) model was developed, and tested with experimental data collected for different gas pressures and liquid feed viscosities. A mesh independence study, as well as some testing of Physics models were performed. A mixed polyhedralprismatic mesh was generated, and the k-ω SST model was selected as it showed a good balance between representation of the turbulence in the system and computational effort. The predicted average lamella thickness is similar with experimental results, with an average 10 % error, but the thickness variations observed in the experiments dampen quickly over time in the simulations. This is not the case in the experiments with the higher viscous maltodextrin solution. Therefore, further model refining has still to be done. Nonetheless, the flow behaves as expected in the CFD simulation with changes in pressure and liquid viscosity. This opens up the possibilities of doing more in-detail CFD studies of the effect of liquid feed properties and geometrical variations of the nozzle.

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“…The atomizing gas is injected into the flowing liquid at a low velocity to create a mixture of bubbly two-phase flow in the mixing chamber before the nozzle exit [1]. Numerical simulation provides an understanding of the internal and external flows in this kind of nozzles [2]. Effervescent atomizers have been used in various engineering applications, such as internal combustion engines, gas turbine combustors, pharmaceutical processes, agricultural sprays, and thermal spray coatings, where pure liquid or complex fluids should be fragmented into small droplets.…”

Section: Introductionmentioning

confidence: 99%

Spray Structure of an Elliptical Effervescent Atomizer

Shaghaghian¹,

Jadidi²,

Dolatabadi³

2020

World Congress on Momentum, Heat and Mass Transfer

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The spray structure of an effervescent atomizer with an elliptical orifice is studied using the high-speed shadowgraphy technique. The major to minor axis ratio of the ellipse is 3. The effect of gas to liquid ratios (GLR) in the range of 0.55-2.55 % on the spray angle is analyzed. The water flow rate was constant for all the tests, while the airflow rate varied. Two imaging views of minor and major axes were captured for each test condition. This study shows that an increase in the gas flowrate results in an increase in the spray angle from both imaging views. It was shown that the spray angle from the minor view is wider than that of the major view, and the difference magnifies by increasing the GLR.

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Numerical study of the effect of gas-to-liquid ratio on the internal and external flows of effervescent atomizers

Cited by 6 publications

References 20 publications

Numerical study of bubbly flow in a swirl atomizer

Numerical study of bubbly flow in a swirl atomizer

Experimental Analysis and CFD Modelling of the Flow Conditions inside an Air-Core-Liquid-Ring Atomizer

Spray Structure of an Elliptical Effervescent Atomizer

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