Development and Validation of a Cascade Atomization and Drop Breakup Model for High-Velocity Dense Sprays

Tanner, Franz X.

doi:10.1615/atomizspr.v14.i3.20

Cited by 72 publications

(32 citation statements)

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“…As in the present work, the simulation of the plasma flow field has been well validated in our previous research [18][19][20]26]. The new modeling of particles, mainly concerning the atomization and vaporization of droplets, is examined here in Figure 3, which displays the evolution of the hot water droplet diameter (d) in the environment of hot gas flow.…”

Section: Validation Of Numerical Modelsupporting

confidence: 59%

“…As demonstrated by Reitz [23], three distinct breakup mechanisms dominated the fragmentation of drops with respect to the gas Weber number: bag breakup, stripping breakup, and catastrophic breakup regimes. The calculation of the Weber number can be found in [18,24]. In this study, the critical Weber number is below 80, which belongs to the bag breakup, as shown in Figure 2.…”

Section: Droplet Atomizationmentioning

confidence: 76%

“…In this study, the droplet tracking and heating states are calculated by a zero-dimensional particle model, and the evaporation of droplets is considered under a flash-boiling condition. The atomization of droplets is illustrated using the cascade atomization and droplet breakup (CAB) model [18].…”

Section: Mathematical Modelmentioning

confidence: 99%

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Investigation of Droplet Atomization and Evaporation in Solution Precursor Plasma Spray Coating

Xiong

Sun

2017

Coatings

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Solution precursor plasma spray (SPPS) is a novel and promising technique in producing nanostructured coatings. This technique involves complex heat, mass and momentum transfer among the liquid feedstock, droplets, plasma jet and the coating material. Nevertheless, the droplet atomization and evaporation in the plasma jet is one of the most essential parts to obtain the desired coating architecture. In the present work, a three-dimensional two-way-coupled Eulerian-Lagrangian code is used to simulate the interactions between the solution precursor and plasma. In order to obtain a more realistic understanding regarding droplet atomization and vaporization, the flash-boiling effect is modeled by an improved vaporization model. This model could provide accurate details for the droplet pyrolysis and help to optimize the solution precursor plasma spray process. We show that the fragmentation of the liquid stock and its vaporization mainly dominate the spraying details and can be decisive to the coating quality. We further investigate their role in SPPS and separately probe their inner link with the flow field relating to the distinctive area when droplets are flying through the thermal flow field. Our studies reveal that ethanol droplets, compared to those of water, show a superior characteristics in SPPS, owing to the low boiling point and low surface tension, conducive to the evaporation and atomization of droplets. In addition, the mixture of the plasma gas with hydrogen breaks the droplets more thoroughly compared to the pure plasma. The numerical results were compared and found to agree well with previous experimental and simulation work.

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Section: Validation Of Numerical Modelsupporting

confidence: 59%

Section: Droplet Atomizationmentioning

confidence: 76%

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Investigation of Droplet Atomization and Evaporation in Solution Precursor Plasma Spray Coating

Xiong

Sun

2017

Coatings

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“…The fuel vapour was allowed to diffuse through the gas culminating in ignition of the fuel vapour/ air mixture. These effects were expected to be accelerated significantly via droplet break-up [50] - [52]. The ignition process was modelled based on the Shell model mentioned above .…”

Section: Heating Evaporation and Ignition Of Fuel Droplets: Combinedmentioning

confidence: 99%

Modelling of heating, evaporation and ignition of fuel droplets: combined analytical, asymptotic and numerical analysis

Sazhin

2005

J. Phys.: Conf. Ser.

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Modelling of heating, evaporation and ignition of fuel droplets: combined analytical, asymptotic and numerical analysis Abstract.The paper discusses recent progress in the development of a combined analytical, asymptotic and numerical approach to modelling of heating and evaporation of fuel droplets and ignition of a fuel vapour/ air mixture. This includes a new approach to combined analytical and numerical modelling of droplet heating and evaporation by convection and radiation from the surrounding hot gas. The relatively small contribution of thermal radiation to droplet heating and evaporation allows us to take it into account using a simplified model, which does not consider the variation of radiation absorption inside droplets. The results of the analysis of the simplified problem of heating and evaporation of fuel droplets and ignition of fuel vapour/ air mixture based on the asymptotic method of integral manifolds are discussed. The semi-transparency of droplets was taken into account in this analysis, and a simplified model for droplet heat-up was used. The results of investigations of the effect of the temperature gradient inside fuel droplets on droplet evaporation, break-up and the ignition of fuel vapour/ air mixture based on a new zero-dimensional code are reviewed. The convection heating of droplets is described in this code based on a combined analytical and numerical approach. A new decomposition technique for a system of ordinary differential equations, based on the geometrical version of the integral manifold method is discussed. This is based on comparing the values of the right hand sides of these equations, leading to the separation of the equations into 'fast' and 'slow' variables. The hierarchy of the decomposition is allowed to vary with time. The application of this technique to analyse the explosion of a polydisperse spray of diesel fuel is presented. It is pointed out that this approach has clear advantages from the point of view of accuracy and CPU efficiency when compared with the conventional approach widely used in CFD codes. IntroductionThe problems of droplet heating, evaporation and ignition of fuel vapour/ air mixture have been widely discussed in the literature [1] - [10]. However, the models used in most practical engineering applications tend to be rather simple. This is due to the fact that droplet heating and evaporation have to be modelled alongside the effects of turbulence, combustion, droplet breakup and related phenomena in realistic 3D enclosures. Hence, finding a compromise between the complexity of the models and their computational efficiency is the essential precondition for successful modelling. In a series of our recent papers [11] -[25] an attempt was made to develop simplified models for droplet heating, evaporation and ignition of fuel vapour/air mixture;

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“…In diesel engines the main emissions of concern are the soot and the NOx emissions which are strongly influenced by the mixture quality inside the fuel spray. Thus, various studies have been carried out which address the spray formation problem and droplet breakup by experiments , by numerical simulations [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40], and by theoretical approaches [44][45][46].…”

Section: Introductionmentioning

confidence: 99%

Effect of Droplet Size and Atomization on Spray Formation: A Priori Study Using Large-Eddy Simulation

Vuorinen

Hillamo

Kaario

et al. 2010

Flow Turbulence Combust

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The paper is mainly focused to the vast number of researchers who work within direct injection (DI) engine fuel spray simulations. The most common simulation framework today within the community is the Reynolds Averaged Navier Stokes (RANS) approach together with the Lagrangian Particle Tracking (LPT) method. In fact, this study is one of the first studies where high resolution LES/LPT diesel spray modeling is considered. The potential of LES to deepen the present day multidimensional LPT fuel spray simulations is discussed. Spray evolution is studied far from an injector by modeling a spray as a particle laden jet (PLJ). The effect of d on mixing in non-atomizing and atomizing sprays is thoroughly investigated at jet inlet Reynolds number Re = 10 4 and Mach number Ma = 0.3. Based on and justified by rather recent and also quite old ideas, novel and compact views on droplet breakup in turb ulent f lows are pointed out from the literature. We use LES/LPT to illustrate that even in a low Weber number flow (We < 13) the droplet breakup modeling may need considerable attention in contrast to what is typically assumed in the present-day breakup models. LES and LPT techniques are first applied to essentially confirm certain expected droplet size effects on spray shape in nonatomizing monodisperse sprays. In the simulations LES e.g. produces an expected turbulent dispersion pattern that depends on droplet diameter (d) without a droplet dispersion model in contrast to RANS. A new compact droplet breakup model is formulated and tested for droplets that break with a natural resonance time rate according to the Poisson process. As a result of the study: 1) the analysis gives a rigorous and enriching proof of currently existing views on droplet size effects on Flow Turbulence Combust (2011) 86:533-561 mixing, and 2) the presented a priori analysis points out the importance of modeling the resonance breakup even at a low We.

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Development and Validation of a Cascade Atomization and Drop Breakup Model for High-Velocity Dense Sprays

Cited by 72 publications

References 0 publications

Investigation of Droplet Atomization and Evaporation in Solution Precursor Plasma Spray Coating

Investigation of Droplet Atomization and Evaporation in Solution Precursor Plasma Spray Coating

Modelling of heating, evaporation and ignition of fuel droplets: combined analytical, asymptotic and numerical analysis

Effect of Droplet Size and Atomization on Spray Formation: A Priori Study Using Large-Eddy Simulation

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