An Investigation into Film Condensation of Saturated Steam on Tube Surfaces by a Gradient Heatmetry

The non-condensable gas effect is a primary concern in some passive systems used in advanced design concepts, such as the Passive Residual Heat Removal System (PRHRS) of AP1000, APR1400, AES-2006, the Passive Containment Cooling System (PCCS) of AP1000 design, and Isolation Condensation System (ICS) of ESBWR design. The accumulation of the non-condensable gas inside the condensing tubes can significantly reduce the level of heat transfer which affects the heat removal capacity in accident condition and impacts plant safety. The objective of the present work is to assess the analysis capability of two wall film condensation models of RELAP5/Mod3.2 with the presence of non-condensable gas in a vertical tube on condensation experiments performed at MIT, USA. The results of the simulations and experimental data show the similar tendencies that the heat transfer coefficients increase as the inlet steam-non condensable gas mixture flow rate increases, the inlet steam-non-condensable gas mass fraction decrease, and the inlet saturated steam temperature decrease

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Film Condensation on Inclined Plane Surfaces

Journal of Heat Transfer ◽

10.1115/1.3450293 ◽

1975 ◽

Vol 97 (1) ◽

pp. 79-82 ◽

Cited By ~ 2

Author(s):

N. V. Suryanarayana ◽

G. L. Malchow

Keyword(s):

Heat Transfer ◽

Atmospheric Pressure ◽

Condensation Heat Transfer ◽

Saturated Steam ◽

Film Condensation ◽

Reduced Gravity ◽

Copper Block ◽

Inclined Plane ◽

Transfer Rates ◽

Gravity Forces

An experimental investigation of the effect of reduced gravity forces on film condensation heat transfer rates was carried out. Reduced gravity conditions parallel to the condensing surface were obtained by condensing saturated steam at atmospheric pressure on one surface of a copper block whose inclination to the vertical could be varied giving effective body forces from 0.1g to 1g in several discrete steps. Condensation heat transfer data were higher than predicted by Nusselt’s correlation. Such increases in heat transfer are shown to be well correlated by an empirical correlation suggested by Kutateladze.

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Recent Improvements of Physical Models in the CATHARE Code and Their Validation

12th International Conference on Nuclear Engineering, Volume 3 ◽

10.1115/icone12-49408 ◽

2004 ◽

Author(s):

I. Dor ◽

G. Geffraye ◽

G. Lavialle ◽

T. Mieusset

Keyword(s):

Experimental Data ◽

Three Dimensional ◽

Equation Model ◽

Physical Models ◽

Saturated Steam ◽

Film Condensation ◽

Entrainment Rate ◽

Two Phase ◽

Pressurized Water ◽

Good Agreement

CATHARE is a system code developed by CEA, EDF, FRAMATOME-ANP and IRSN for Pressurized Water Reactor (PWR) safety analysis. Two-phase Flows are described using a Two-Fluid Six-equation model (1 D module) and the presence of non-condensable gases can be taken into account by one to four additive transport equations. The code allows a three-dimensional modelling of the Pressure Vessel (3D module). Successive sets of closure laws are developed in an iterative methodology of improvement. The main recent developments are presented and discussed. Film condensation of steam in presence of nitrogen and helium in a tube has been investigated in the COTURNE experiment. The liquid film heat transfer coefficient is first investigated in pure saturated steam for the wavy laminar film regime. In presence of non-condensable gases, the mass diffusion of steam in the gas mixture is modelled using a Sherwood number and a heat and mass transfer analogy. The code shows good agreement with the COTURNE tests and with other experimental data of Siddique & al and Nagasaka & al. The CATHARE capability to well represent the entrainment of liquid from the upper plenum to the steam generator inlet chamber is validated using MHYRESA experimental data. A new stratified interfacial friction based on experimental data analysis leads to satisfactory CATHARE predictions compared to MHYRESA and UPTF-TRAM data. The CATHARE 3D module capability to well calculate the refilling phase of the lower plenum considering the multi-dimensional effects is validated using UPTF tests. Two types of tests are considered to separate mechanical and condensation effects. Considering a specific entrainment rate and condensation rate for such an annular downcomer, CATHARE predictions are in good agreement with the experimental results. The BETHSY test 9.1b (ISP27) consists of 2-inch cold leg break with an ultimate procedure actuated on a cladding temperature criterion. The comparison between the calculation and the experimental data shows a rather good agreement.

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FORCED CONVECTION FILM CONDENSATION ON A HORIZONTAL TUBE WITH VARIABLE PROPERTIES

Journal of Mechanical Engineering ◽

10.3329/jme.v40i2.5347 ◽

2010 ◽

Vol 40 (2) ◽

pp. 79-89 ◽

Cited By ~ 1

Author(s):

Bodius Salam ◽

David A. A. McNeil ◽

Bryce M. Burnside ◽

Sumana Biswas

Keyword(s):

Tube Wall ◽

Property Values ◽

Horizontal Tube ◽

Boundary Layer Separation ◽

Saturated Steam ◽

Film Condensation ◽

Variable Properties ◽

Constant Property ◽

Pressure Distributions ◽

The Mean

The paper presents the results of numerical calculations for filmwise condensation of downward flowing pure saturated steam on a horizontal tube. A tube of 19.05 mm diameter was used. Steam approach conditions used were 5000 N/m2 (Tsat = 32.9 oC) pressure and velocity 5 – 100 m/s. Tube wall temperatures were considered to be constant at 22.9 oC and 30.9 oC, giving condensate subcooling DT = 10 K and 2 K respectively. Earlier theoretical studies omitted the variations of physical properties with pressure arising from flow of vapor over the tube surface. The present work takes into account these property variations. The velocity and pressure distributions were taken from the potential flow theory. At low condensate subcooling, DT = 2 K, and high steam velocities, significant reduction of average heat transfer coefficient was predicted when property variations were taken into account, compared to constant property values. The mean heat flux predicted considering the variation of properties was up to 9% and 42% less than that obtained for DT = 10 K and 2 K respectively.Keywords: Laminar filmwise condensation; horizontal tube; boundary layer separation; numerical.DOI: 10.3329/jme.v40i2.5347Journal of Mechanical Engineering, Vol. ME 40, No. 2, December 2009 79-89

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