Two-Phase Flow, Boiling, and Condensation

Ghiaasiaan, S. Mostafa

doi:10.1017/9781316597392

Cited by 55 publications

(27 citation statements)

References 595 publications

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“…Without it, the wall shear stress is under-estimated because the velocity gradient across the thin liquid film cannot be taken into account which results in significantly over-predicted liquid velocity. With the implemented model, the predicted liquid velocity and the film thickness are in reasonably good agreement with the analytical solution after being fully-developed and the STAR-CCMþ calculation results as presented in A wall film condensation model was implemented into CUPID after the implementation of the liquid film model, which combines the models proposed by Ghiaasiaan [24] and Naylor and Friedman [27]. The following are the equations for the wall film condensation model.…”

Section: Implementation Of Film Condensation Model Into Cupidmentioning

confidence: 58%

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Improvement of CUPID code for simulating filmwise steam condensation in the presence of noncondensable gases

Lee

Park

Cho

2015

Nuclear Engineering and Technology

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a b s t r a c tIn a nuclear reactor containment, wall condensation forms with noncondensable gases and their accumulation near the condensate film leads to a significant reduction in heat transfer. In the framework of nuclear reactor safety, the film condensation in the presence of noncondensable gases is of high relevance with regards to safety concerns as it is closely associated with peak pressure predictions for containment integrity and the performance of components installed for containment cooling in accident conditions. In the present study, CUPID code, which has been developed by KAERI for the analysis of transient twophase flows in nuclear reactor components, is improved for simulating film condensation in the presence of noncondensable gases. In order to evaluate the condensate heat transfer accurately in a large system using the two-fluid model, a mass diffusion model, a liquid film model, and a wall film condensation model were implemented into CUPID. For the condensation simulation, a wall function approach with a heat/mass transfer analogy was applied in order to save computational time without considerable refinement for the boundary layer. This paper presents the implemented wall film condensation model, and then introduces the simulation result using the improved CUPID for a conceptual condensation problem in a large system.

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Section: Implementation Of Film Condensation Model Into Cupidmentioning

confidence: 58%

“…This exchange of information between CUPID and the liquid film model is repeated for all wall cells at every time step. The liquid film model is presented by Ghiaasiaan [24] with a fully developed liquid film assumption. The momentum equation of a liquid film is:…”

Section: Implementation Of Film Condensation Model Into Cupidmentioning

confidence: 99%

Improvement of CUPID code for simulating filmwise steam condensation in the presence of noncondensable gases

Lee

Park

Cho

2015

Nuclear Engineering and Technology

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“…6(c), heat transfer coefficient decreases as saturation temperature increases. These trends are typical for evaporation in tubes (Collier and Thome [30], Ghiaansiaan [31]). As mass flux or quality increases, the flow momentum increases, yielding a high heat transfer coefficient.…”

Section: Evaporation Heat Transfer Coefficientmentioning

confidence: 75%

Evaporation heat transfer and pressure drop of R-410A in three 7.0 mm O.D. microfin tubes having different inside geometries

Kim

2015

J Mech Sci Technol

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R-410A evaporation heat transfer and pressure drop data are provided for three 7.0 mm O.D. microfin tubes. The microfin tubes had different helix angle, fin height and fin apex angle. Tests were conducted for a range of quality (0.2 ~ 0.8), mass flux (216 ~ 390 kg/m 2 s), heat flux (9 ~ 17 kW/m 2 ) and saturation temperature (8 ~ 12 o C). It was found that three microfin tubes yielded approximately the same heat transfer coefficients. Microfin tube with larger inter-fin spacing or smaller helix angle yielded lager pressure drop. Both heat transfer coefficient and pressure drop increased as mass flux or quality increased. However, they decreased as saturation temperature increased. The range of heat transfer enhancement factor (1.37 ~ 1.97) was comparable with that of pressure drop penalty factor (1.22 ~ 1.77). Data are compared with available heat transfer and pressure drop correlations.

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“…This long-standing problem is of great complexity because flowing fluids are often far away from thermal equilibrium (e.g., during chilldown), and their dynamics involves heat and mass transfer [2][3][4]. A sketch of the two-phase flow is shown in the Figure 1.…”

Section: Introductionmentioning

confidence: 99%

“…A sketch of the two-phase flow is shown in the Figure 1. Within the accepted approximation [3,4], the pressure p in the system is common. The temperature of the wall T w , vapor T g , and liquid T l can all be different.…”

Section: Introductionmentioning

confidence: 99%

Two-Phase Flow Modeling of Cryogenic Loading Operations

Devine¹,

Luchinsky²,

Foygel³

et al. 2019

Heat and Mass Transfer - Advances in Science and Technology Applications

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We consider problem of modeling and controlling two-phase cryogenic flows during ground loading operations. We introduce homogeneous moving front and separated two-phase flow solvers that are capable of fast and accurate online predictions of flow dynamics during chilldown and transfer under nominal conditions and in the presence of faults. Concise sets of cryogenic correlations are proposed in each case. We present results of application of proposed solvers to the analysis of chilldown in large-scale experimental cryogenic transfer line build in Kennedy Space Center. We discuss optimization of parameters of cryogenic models obtained using general inferential framework and an application of the solvers to the fault detection and evaluation based on D-matrix approach. It is shown that solver's predictions are in good agreement with experimental data obtained for liquid nitrogen flow in nominal regime and in the presence of faults.

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Two-Phase Flow, Boiling, and Condensation

Cited by 55 publications

References 595 publications

Improvement of CUPID code for simulating filmwise steam condensation in the presence of noncondensable gases

Improvement of CUPID code for simulating filmwise steam condensation in the presence of noncondensable gases

Evaporation heat transfer and pressure drop of R-410A in three 7.0 mm O.D. microfin tubes having different inside geometries

Two-Phase Flow Modeling of Cryogenic Loading Operations

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