Condensation Coefficient: Definitions, Estimations, Modern Experimental and Calculation Data

Kryukov, A. P.; Levashov, V. Yu.; Pavlyukevich, N. V.

doi:10.1007/s10891-014-1006-4

Cited by 20 publications

(6 citation statements)

References 7 publications

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“…[9][10][11][12][13][14][15][16][17][18][19][20]). As one of the methods to avoid the ambiguities introduced in the process of assigning evaporating or reflecting molecules based on MD simulations, a concept of spontaneous evaporation was assumed [12], and the molecular mass flux due to spontaneous evaporation was confirmed with MD simulation based on virtual-vacuum evaporation [10,12].…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics study on evaporation and reflection of monatomic molecules to construct kinetic boundary condition in vapor–liquid equilibria

et al. 2015

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Using molecular dynamics simulations, the present study investigates the precise characteristics of evaporating and reflecting monatomic molecules (argon) composing a kinetic boundary condition (KBC) in a vapor-liquid equilibria. We counted the evaporating and reflecting molecules utilizing two boundaries (vapor and liquid boundaries) proposed by the previous studies (Meland et al., in Phys Fluids 16:223-243, 2004, and Gu et al., in Fluid Phase Equilibria 297:77-89, 2010). In the present study, we improved the method using the two boundaries incorporating the concept of the spontaneously evaporating molecular mass flux. The present method allows us to count the evaporating and reflecting molecules easily, to investigate the detail motion of the evaporating and reflecting molecules, and also to evaluate the velocity distribution function of the KBC at the vapor-liquid interface, appropriately. From the results, we confirm that the evaporating and reflecting molecules in the normal direction to the interface have slightly faster and significantly slower average velocities than that of the Maxwell distribution at the liquid temperature, respectively. Also, the stall time of the reflecting molecules at the interphase that is the region in the vicinity of the vapor-liquid interface is much shorter than those of the evaporating molecules. Furthermore, we discuss our method for constructing the KBC that incorporates condensation and evaporation coefficients. Based on these results, we suggest that the proposed method

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Section: Introductionmentioning

confidence: 99%

Molecular dynamics study on evaporation and reflection of monatomic molecules to construct kinetic boundary condition in vapor–liquid equilibria

et al. 2015

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“…However, in the authors' attempt in this direction, the following difficulties have been encountered [6]. Let us suppose that a liquid layer of water with a thickness (x) of 1 cm is studied.…”

Section: Difficulties Of Boundary Conditions Formulationmentioning

confidence: 99%

“…The temperature of the vapor phase differs from the liquid temperature. More detail information about our modeling of the gas and liquid phase is given in references [6,20].…”

Section: Molecular Dynamics Simulation Proceduresmentioning

confidence: 99%

Boundary conditions on the vapor liquid interface at strong condensation

Kryukov

Levashov

2015

Heat Mass Transfer

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“…The largest values of the condensation coeffi cient, 0.1 < f ≤ 1, were obtained in the case where the phase transition occurred on a fresh surface: evaporation into a vacuum proceeds at a high rate and the duration of evaporation from the fresh surface of a jet increases to about 3 ms [19,20]. For further investigations, the methods of molecular dynamics are of promise [21].…”

mentioning

confidence: 99%

Effect of Surface Phenomena on Evaporation and Condensation of Water Systems

Kochurova

Korotkikh

Abdulin

et al. 2016

J Eng Phys Thermophy

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Experimental results for the dynamic surface tension, surface electrization, and for the rate of evaporation (condensation) of water systems are presented.Introduction. "The Niagara has frozen!" This information together with the fascinating pictures of the waterfall in America appeared on the Internet in mid-January, 2014 ( Fig. 1) [1]. The explanation of this phenomenon is that at the place of a sharp change in the liquid fl ow, separate parts of its vertical jets intermix and the elements of its bulk structure appear on the liquid surface. As the experiments carried out by Hiekman [2] showed ( Fig. 2), as the rate of evaporation from a fresh liquid surface increases, the infl uence of the gases near its moving surface is reduced considerably, and the cooling of the liquid increases drastically.The icing of a rapidly fl owing, freshly formed surface of water can be explained by taking into account its peculiar properties under dynamic conditions. The properties of the interface exert a substantial effect on the progress of a large variety of natural processes, including also the evaporation-condensation kinetics that determines the operation of machines and apparatuses, evaporator systems, distillers, and other facilities. In designing industrial apparatuses, the molecular phenomena occurring on the interfaces are to be taken into account in heat and mass transfer calculations.Dynamic Surface Tension. The dynamic surface tension is the tension of a freshly formed nonequilibrium surface of a liquid jet, bubbles, and droplets. An experimental investigation of the dynamic surface tension was carried out by the methods of an oscillating jet and of a maximum pressure in a gaseous bubble with some improvements made in the technique of measurements with account for the liquid fl ow velocity profi le and for the recovery of the forming surface [3]. Water, a number of solutions of inorganic salts, surfactant solutions, dimethylformamide, and other substances were investigated.The most interesting, stably recurring feature of the dynamic surface tension is the temperature inversion: at a very early age of the surface (t = 1-3 ms) and a low concentration of a solution in the temperature range 10-25 o C, the surface tension increases with temperature T. The data for water are presented in Fig. 3 [3].The temperature inversion was observed at a young age of the surface for water and water solution of NaCl in the early works of Schmidt and Steyer [4], as well as Kleinman [5], who used the method of a falling meniscus to measure the dynamic surface tension. The measurements made by Owens [6] for a NaCl solution by the method of an oscillating jet also show that at short times the temperature inversion is possible. On increase in the temperature up to 10 o C and above, the surface tension increases and then decreases.Special experiments with a water jet showed that heating of the jet up to 40-50 o C leads to an equilibrium value of surface tension. For water, the temperature in the region of 30-40 o C is known as the Mendeleev ...

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Condensation Coefficient: Definitions, Estimations, Modern Experimental and Calculation Data

Cited by 20 publications

References 7 publications

Molecular dynamics study on evaporation and reflection of monatomic molecules to construct kinetic boundary condition in vapor–liquid equilibria

Molecular dynamics study on evaporation and reflection of monatomic molecules to construct kinetic boundary condition in vapor–liquid equilibria

Boundary conditions on the vapor liquid interface at strong condensation

Effect of Surface Phenomena on Evaporation and Condensation of Water Systems

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