Droplet phase change model and its application in wave-type vanes of steam generator

Zhao, Fulong; Zhao, Chen; Bo, Hanliang

doi:10.1016/j.anucene.2017.06.055

Cited by 17 publications

(10 citation statements)

References 30 publications

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“…In order to simplify the complex phenomena and formulate a precise droplet motion and phase change model, four hypotheses are present (Zhao et al, 2018) as follows: (1) The temperature within the droplet is uniform. As the radii of the spray droplets are usually less than 500 μm, the Biot number is below 0.1.…”

Section: Hypothesismentioning

confidence: 99%

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Application of droplet motion and evaporation model in fuel spray in the constant volume bomb

Meng

Yan²,

Zhao

et al. 2019

JTST

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The fuel oil atomization is closely related to the combustion performance of the fuel in the internal combustion engine. However, during the oil atomization, the fast evaporating and moving oil droplets interact strongly with the surrounding gas, posing challenges towards the precise simulation of the combustion process. To precisely capture the interactions between fuel droplets and the surrounding gas, a new multi-droplets motion and evaporation model is deduced by introducing the local parameters surrounding the fuel droplets. The proposed model is validated comparing the simulation results against the experimental data of the containment spray process. Subsequently, the present model is adopted to simulate the fuel spray process in the typical constant volume bomb. The parameters evolution is presented during the course of the spray such as the gas temperature, droplet temperature, evaporating rate, velocity, radii variation, vapor concentration and air-fuel ratio. The analysis of the spray performance is conducted and the superiority of the new model is also discussed. The simulation analysis reveals that the spray droplets interact strongly with the surrounding gas; the developed droplet motion and evaporation model is advantageous in the simulation of the dense multi-droplets spray process.

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Section: Hypothesismentioning

confidence: 99%

“…For the moving droplets carried by the surrounding gas in the containment, they will be affected by the gravity, additional mass force, buoyancy, drag force, Magnus lift force and Saffman lift force (Zhang et al, 2015;Zhao et al, 2018).…”

Section: Droplet Motion Modelmentioning

confidence: 99%

Application of droplet motion and evaporation model in fuel spray in the constant volume bomb

Meng

Yan²,

Zhao

et al. 2019

JTST

Self Cite

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“…The phase change model includes the mass transfer model, heat transfer model, and vapor velocity equation due to pressure difference (Zhao et al, 2018). The mass transfer model is comprised of the hydrodynamic model and kinetic model.…”

Section: Mass Transfer Equationmentioning

confidence: 99%

“…As the dispersed droplet moves in the separator, the steam vapor pressure decreases gradually along the flow direction. The droplet may evaporate due to the effect of the pressure difference between the droplet and the surrounding steam vapor (Zhao et al, 2018). In addition, the droplet evaporation phenomena due to depressurization exist in numbers of the industrial fields such as the seawater desalination, ocean thermal energy conversion power plants, steam accumulator, and cooling of high temperature part of the space shuttle.…”

Section: Introductionmentioning

confidence: 99%

Ratio analysis of two mechanisms of static droplet evaporation driven by pressure difference

Zhao

Liu

Lin

et al. 2019

Exp. Comput. Multiph. Flow

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When droplet moving in the steam-water separator, the gas pressure will decrease due to flow resistance and the liquid-vapor equilibrium at the droplet surface will be broken. The droplet evaporates continuously as a result. The fast evaporation mechanism and thermal balance evaporation mechanism are presented for the droplet evaporation at cases of pressure variation. The droplet phase change model due to pressure variation is formulated. Subsequently, the effects of pressure difference on the droplet evaporation characteristics are analyzed. The ratio analysis of the two mechanisms is conducted. The droplet evaporation map over the ratio of two mechanisms is drawn. The numerical results indicate that the pressure difference significantly influences the droplet evaporation characteristics. Under most conditions, the droplet evaporation characteristics are dominated by the combined action of two mechanisms. For large pressure difference and small droplets, the fast evaporation mechanism dominates the evaporation process, and vice versa. With increasing pressure difference between the droplet and the surrounding environment, the droplet evaporates faster and the percentage of fast evaporation mechanism decreases gradually. The present work can lay the foundation for further investigation on the moving droplet evaporation.

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“…The calculation using this model is only possible with a sufficiently large number of particles and with small values of volumetric water content [9].…”

Section: Particle Transport Modelmentioning

confidence: 99%

Numerical investigation of a moisture wave-type vane separator

2019

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This study aims to determine the appropriate method for modeling separation processes in wave-type moisture vane separators and to analyze possible design improvements of the typical wave-type vane separator using numerical simulation methods. It discusses conditions of the secondary droplets generation phenomena. The applicability of the particle transport method for modeling the working process in wave-type vane separators is confirmed. The study explores the water droplets distribution pattern in the dispersed two-phase flow of a separator. A numerical study of the workflow in the typical steam-water separator with wave-type vanes was carried out. A dispersed two-phase flow in a separator is modelled as two separate flows. Dry saturated steam is considered as a continuous medium using the Euler method; the liquid phase is represented as a stream of water droplets described by the Lagrange method. Authors propose an option of modernization of the separator design applying three drainage channels on the path of small droplets.

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Droplet phase change model and its application in wave-type vanes of steam generator

Cited by 17 publications

References 30 publications

Application of droplet motion and evaporation model in fuel spray in the constant volume bomb

Application of droplet motion and evaporation model in fuel spray in the constant volume bomb

Ratio analysis of two mechanisms of static droplet evaporation driven by pressure difference

Numerical investigation of a moisture wave-type vane separator

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