Features of Mass Transfer of Noncondensable Gases by Primary Coolant of Nuclear Icebreaker Reactors

Atomic Energy ◽  
2019 ◽  
Vol 127 (2) ◽  
pp. 77-82
Author(s):  
V. E. Karnaukhov ◽  
V. S. Ustinov ◽  
D. S. Urtenov ◽  
Yu. B. Vorob’ev ◽  
Yu. B. Zudin ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Primary Coolant ◽  
Noncondensable Gases

Diffusion Layer Theory for Turbulent Vapor Condensation With Noncondensable Gases

1993 ◽  
Vol 115 (4) ◽  
pp. 998-1003 ◽  
Author(s):  
P. F. Peterson ◽  
V. E. Schrock ◽  
T. Kageyama
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Mass Transfer ◽  
Vapor Condensation ◽  
Sensible Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Noncondensable Gas ◽  
Noncondensable Gases ◽  
Vertical Tubes

In turbulent condensation with noncondensable gas, a thin noncondensable layer accumulates and generates a diffusional resistance to condensation and sensible heat transfer. By expressing the driving potential for mass transfer as a difference in saturation temperatures and using appropriate thermodynamic relationships, here an effective “condensation” thermal conductivity is derived. With this formulation, experimental results for vertical tubes and plates demonstrate that condensation obeys the heat and mass transfer analogy, when condensation and sensible heat transfer are considered simultaneously. The sum of the condensation and sensible heat transfer coefficients becomes infinite at small gas concentrations, and approaches the sensible heat transfer coefficient at large concentrations. The “condensation” thermal conductivity is easily applied to engineering analysis, and the theory further demonstrates that condensation on large vertical surfaces is independent of the surface height.

scholarly journals Numerical Investigation of Natural Convective Condensation with Noncondensable Gases in the Reactor Containment after Severe Accidents

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Wen Fu ◽  
Li Zhang ◽  
Xiaowei Li ◽  
Xinxin Wu
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Mass Fraction ◽  
Transfer Processes ◽  
Noncondensable Gases ◽  
Mass Transfer Processes ◽  
Convective Condensation

The heat and mass transfer processes of natural convective condensation with noncondensable gases are very important for the passive containment cooling system of water cooled reactors. Numerical simulation of natural convective condensation with noncondensable gases was realized in the Fluent software by adding condensation models. The scaled AP600 containment condensation experiment was simulated to verify the numerical method. It was shown that the developed method can predict natural convective condensation with noncondensable gases well. The velocity, species, and density fields in the scaled AP600 containment were presented. The heat transfer rate distribution and the influences of the mass fraction of air on heat transfer rate were also analyzed. It is found that the driving force of natural convective condensation with noncondensable gases is mainly caused by the mass fraction difference but not temperature difference. The natural convective condensation with noncondensable gases in AP1000 containment was then simulated. The temperature, species, velocity, and heat flux distributions were obtained and analyzed. The upper head of the containment contributes to 35.1% of the total heat transfer rate, while its area only takes 25.4% of the total condensation area of the containment. The influences of the mass fraction of low molecular weight noncondensable gas (hydrogen) on the natural convective condensation were also discussed based on the detailed species, density, and velocity fields. The results show that addition of hydrogen (production of zirconium-water reaction after severe accident) will weaken the intensity of natural convection and the heat and mass transfer processes significantly. When hydrogen contributes to 50% mole fraction of the noncondensable gases, the heat transfer coefficient will be reduced to 45%.

Effect of an Inert Gas on Heat and Mass Transfer in a Vertical Channel With Falling Films

1997 ◽  
Vol 119 (1) ◽  
pp. 24-30 ◽  
Author(s):  
Wei Chen ◽  
G. C. Vliet
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Film Flow ◽  
Vertical Channel ◽  
Reynolds Numbers ◽  
Momentum Equation ◽  
Limited Data ◽  
Low Reynolds Numbers ◽  
Noncondensable Gases ◽  
Energy Equations

The effect of inert (noncondensable) gases on the heat and mass transfer (absorption) for channel flow of water vapor in conjunction with falling aqueous LiBr films is investigated. The hydrodynamic flow of the gas in the channel is approximated as fully developed. This is a “fair” assumption because of the low Reynolds numbers resulting from the low prevailing absorber pressures. The film flow is also assumed to be hydrodynamically developed. This greatly simplifies the problem, as the momentum equation need not be considered. Otherwise the continuity, species, and thermal energy equations govern the problem. Numerical results for a nominal case are presented for the velocity, temperature, and species distributions in the gas and liquid phase regions, and for the interface absorption rate. The effects of varying several parameters (including inerts concentration) on the above variables are also presented. Comparisons are also made with limited data in the literature.

Turbulent Flow, Heat Transfer, and Mass Transfer in a Tube With Surface Suction

1970 ◽  
Vol 92 (1) ◽  
pp. 117-124 ◽  
Author(s):  
R. B. Kinney ◽  
E. M. Sparrow
Keyword(s):  
Mass Transfer ◽  
Transverse Velocity ◽  
Turbulent Transport ◽  
Turbulent Pipe Flow ◽  
Transfer Coefficients ◽  
Cross Sectional ◽  
Noncondensable Gases ◽  
Axial Pressure Gradient ◽  
Flow Heat ◽  
Impermeable Boundary

The problem of turbulent pipe flow with mass removal at the bounding surface is analyzed, and numerical results are presented for the friction factor, axial pressure gradient, heat and mass transfer coefficients, and velocity and temperature profiles. The results, which are relevant to forced-convection condensation in a tube (either with or without noncondensable gases) are shown to be substantially affected by even small amounts of wall suction. Therefore, the present findings do not support the current practice of using impermeable-boundary transfer coefficients in condensation calculations. The analysis is performed under the condition that the velocity field is locally self-similar. Corresponding conditions are used for the distributions of temperature and mass fraction. The cross-sectional distributions of the transverse velocity and the shear stress are not constrained in advance, but rather, are permitted to vary in accordance with the conservation laws. The turbulent transport is expressed in terms of the mixing-length, model, modified in the neighborhood of the wall by a specially derived dumping factor.

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