Numerical investigation of spray characteristics of an air-blast atomizer with dynamic mesh

Shafaee, Maziar; Mahmoudzadeh, Sajad

doi:10.1016/j.ast.2017.08.024

Cited by 20 publications

(14 citation statements)

References 10 publications

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“…This software is widely used today, especially for modeling twophase flows including sprays. [39][40][41] The geometrical features and flow characteristics of the jet-swirl injector are obtained by applying the method provided by Bayvel and Orzechowski. 7 Jet-swirl full-cone atomizer Schematic of full-cone and hollow-cone pressure-swirl atomizers are shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of the full-cone spray structure and characteristics provided by a jet-swirl atomizer

Hassani

Elkaie

Shafaee

2019

Proceedings of the Institution of Mechanical Engineers, Part G:

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Jet-swirl atomizers are one of the pressure-swirl atomizers that produce full-cone spray. Although many hollow-cone pressure-swirl sprays have been studied, characteristic investigation of pressure-swirl full-cone sprays are limited to a few experimental, analytical, and numerical works where each of them investigate some of the main spray parameters. The few existing numerical studies are limited to calculate the coefficient of discharge and spray cone angle. Current numerical study investigate a newly developed jet-swirl atomizer with pressure-swirl full-cone spray, which considers other important full-cone spray characteristics including Sauter mean diameter, D10, and spray tip penetration along with the spray structure. In this study, a full-cone spray based on a newly developed jet-swirl injector is numerically simulated and analyzed using sprayFoam solver in the OpenFOAM 4.1 software. The existing code of the solver is developed and its dictionary is modified. The C+ + Sauter mean diameter and D10 codes on the cross-sectional surface are developed and this feature is added to the sprayFoam solver. The pre-published experimental and current work numerical results were in good agreement. In the simulation process, blob sheet model is used for the spray primary breakup. Two models including Taylor analogy breakup and Reitz–Diwakar have been used for the secondary breakup of the developed jet-swirl atomizer. This work shows that the results of the Reitz–Diwakar model are close to that of the Taylor analogy breakup model. The time-varying results of Sauter mean diameter, D10, and spray tip penetration are found to be in good agreement in both models. The results show that the Reitz–Diwakar model is stabilized somewhat later than the Taylor analogy breakup model. The simulated spray structure shows that the density of droplets is higher in the spray center region and this density is gradually reduced through the radial direction. The results along the radius show that the diameter of the droplets becomes larger while moving away from the center of the spray.

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Section: Introductionmentioning

confidence: 99%

Numerical investigation of the full-cone spray structure and characteristics provided by a jet-swirl atomizer

Hassani

Elkaie

Shafaee

2019

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…The standard k − ε model is based on the model transport equations for the turbulence kinetic energy ( k ) and its dissipation rate ( ε ) in the Reynolds-averaged Navier-Stokes (RANS) equations. In recent studies, researchers applied alternative, more accurate numerical methods to simulate the turbulent flow in engineering problems, such as the renormalization group (RNG) k − ε model (Shafaee and Mahmoudzadeh, 2017), direct numerical simulation (DNS) method (Prakash et al , 2019) and large eddy simulation (LES) method (Zhu et al , 2019; Yoo et al , 2017). However, the standard k − ε models were used in the present study because the use of a computational resource-saving numerical strategy is critical in engineering design processes.…”

Section: Numerical Modelling and Evaluation Criteriamentioning

confidence: 99%

“…The injection angle α is a key design parameter for air-blast atomizer. Shafaee et al (2011), Shafaee and Mahmoudzadeh (2017) investigated the effect of the geometrical parameters on the atomization performance by analysing the experimental and numerical results. Shafaee and Mahmoudzadeh (2017) demonstrated that the variation in the injection angle α did not considerably influence the Sauter mean diameter (SMD) and spray penetration depth in the external region of this atomizer.…”

Section: Introductionmentioning

confidence: 99%

“…Shafaee et al (2011), Shafaee and Mahmoudzadeh (2017) investigated the effect of the geometrical parameters on the atomization performance by analysing the experimental and numerical results. Shafaee and Mahmoudzadeh (2017) demonstrated that the variation in the injection angle α did not considerably influence the Sauter mean diameter (SMD) and spray penetration depth in the external region of this atomizer. In addition, Fuller et al (1997) indicated that the injection angle α considerably influenced the behaviour of a liquid column and it could influence the spray structures in the external region.…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of the effect of the injection angle on the spray structures of an air-blast atomizer

Sheng

Xing

Liu

et al. 2020

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Purpose The purpose of this study is to investigate the effect of the injection angle α on the spray structures of an air-blast atomizer and help enhance the understanding of droplet-gas mixing process in such atomizers in the engineering domain. Design/methodology/approach The phenomena in the air-blast atomizer were numerically modelled using the computational fluid dynamics software Fluent 17.2. The Euler-Lagrange approach was applied to model the droplet tracking and droplet-gas interaction in studied cases. The standard k-ε model was used to simulate the turbulent flow. A model with a modified drag coefficient was used to consider the effects of the bending of the liquid column and its penetration in the primary breakup region. The Kelvin-Helmholtz, Rayleigh-Taylor model was applied to consider the secondary breakup of the droplets. Findings The basic spatial distribution and spray structures of the droplets corresponding to the angled liquid jet (α = 60°) were similar to those reported in liquid jets injected transversely into a gaseous crossflow studies. The injection angle α did not considerably influence the averaged Sauter to mean diameter (SMD) of the cross-sections. However, the spray structures pertaining to α = 30°, α = 60° and α = 90° were considerably different. In the case of the atomizer with multiple injections, a “collision region” was observed at α = 60° and characterized by a higher ci and larger averaged SMD in the central parts of the cross-sections. Originality/value The injection angle α is a key design parameter for air-blast atomizers. The findings of this study can help enhance the understanding of the droplet-gas mixing process in air-blast atomizers. Engineers who design air-blast atomizers and face new challenges in the process can refer to the presented findings to obtain the desired atomization performance. The code has been validated and can be used in the engineering design process of the gas-liquid jet atomizer.

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“…For the simple steady flow, the mesh could be refined to improve the accuracy of iteration, which is investigated and proved by Niu et al [22][23][24]. But, for some complex flow fields which are attempted by Shafaee [25], Adam [26] and Xiong [27], both of the mesh quality and interval time after mesh reconstruction could not be work out effectively.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of internal flow characteristics in a mixed-flow pump with eccentric impeller

Shi

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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In order to study the internal flow fields of mixed-flow pump with eccentric impeller, the numerical simulation and experiment have been conducted based on the dynamic sliding multi-region method. During simulation, the impeller domain has been separated by three sub-domains to apply the whirl effect. The pressure, turbulent kinetic dissipation and streamline distribution in the tip clearance were analyzed. The results show that the energy performance of calculation is basically consistent with the experimental results, which indicates the accuracy of energy performance prediction. The efficiency and head at the design flow condition drop about 20% and 11%, respectively, when e = 0.5 mm. The circumferential pressure distribution of impeller inlet and outlet is influenced greatly by the eccentric impeller, but the middle part of impeller suffered little effects as a result of the rotation effect of impeller. When the impeller is eccentric, the tip leakage flow and tip leakage vortex (TLV) are restrained at small tip clearance but enhance at large tip clearance. The angle between the TLV core and blade rim also increases at large tip clearance but decreases at small tip clearance. More energy has dissipated in the first half part of impeller channel within tip region, and the impacting depth increases with the increase in eccentricity, which affect the inlet flow fields of impeller at large eccentricity. The turbulent kinetic dissipation and hydraulic losses increase with the increase in eccentricity, which is the main factor for the decrease in pump efficiency.

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Numerical investigation of spray characteristics of an air-blast atomizer with dynamic mesh

Cited by 20 publications

References 10 publications

Numerical investigation of the full-cone spray structure and characteristics provided by a jet-swirl atomizer

Numerical investigation of the full-cone spray structure and characteristics provided by a jet-swirl atomizer

Numerical investigation of the effect of the injection angle on the spray structures of an air-blast atomizer

Numerical investigation of internal flow characteristics in a mixed-flow pump with eccentric impeller

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