Burn-out, circumferential film flow distribution and pressure drop for an eccentric annulus with heated rod

doi:10.1016/0301-9322(74)90009-3

International Journal of Multiphase Flow

Volume 1, Issue 4, 30 October 1974, Pages 585-600

https://doi.org/10.1016/0301-9322(74)90009-3 Get rights and content

Abstract

Measurements of (1) burn-out, (2) circumferential film flow distribution, and (3) pressure drop in a $17 × 27.2 × 3500 mm$ concentric and eccentric annulus geometry are presented. The eccentric displacement was varied between 0 and 3 mm. The working fluid was water. Burn-out curves at 70 bar are presented for mass velocities between 500 and 1500 kg/m²s and for inlet subcoolings of 10°C and 100°C. The film flow measurements correspond to the steam qualities $χ = 19 %$ and 24 % for the mass velocity $G = 602$ kg/m²s and $χ = 20 %$ and 23 % for $G = 1200$ kg/m²s. The influence of the circumferential rod film flow variation on burn-out is discussed.

References (2)

D. Butterworth
Air—water climbing film flow in an eccentric annulus
U.K.A.E.A., Report No. AERE-R5787
(May 1968)
F.A. Schraub et al.
Two-phase flow and heat transfer in multirod geometries

Cited by (7)

Progress in understanding and modelling of annular two-phase flows with heat transfer
2019, Nuclear Engineering and Design
Citation Excerpt :
Similar asymmetry was observed by Mannov (1973), Jensen and Mannov (1974) and Würtz (1978). For eccentric annuli the situation is somewhat unclear: Schraub et al. (1969) and Andersen et al. (1974) observed a minimum film flow rate at the minimum gap. In contrast, Butterworth (1968) measured uniform film flow distribution in an eccentric annulus and found the thickest film at the narrow gap.
Annular two-phase flows with heat transfer play important role in many industrial applications. In particular, thermal margins of Boiling Water Reactors (BWR) are entirely determined by this type of flow and heat transfer conditions. To avoid dryout, a liquid film must be present on heated rods of BWR fuel assemblies during normal operation. The present paper describes the recent progress in understanding and modelling of the governing phenomena of annular two-phase flow and heat transfer. A special attention has been devoted to experimental observations that have the most significant influence on the adopted modelling approach. The primary goal is to pave a path to mechanistic modelling of dryout and post-dryout heat transfer applicable to nuclear fuel assemblies. Current Computational Fluid Dynamics (CFD) approaches to model the governing phenomena are presented and their further improvements are suggested.
Critical Heat Flux
1985, Advances in Heat Transfer
This chapter defines critical heat flux (CHF). If a heated surface is wet with liquid, and most of the heat transferred to the liquid is absorbed by the latent heat of evaporation in the vicinity of the heated surface, then a large amount of heat can be transferred with a very small temperature difference. However, this excellent state of heat transfer is not boundless, and the upper boundary of heat flux that exists as a necessary consequence is termed CHF. This chapter introduces CHF in fundamental boiling systems. It may be a bit hazardous to undertake a systematic explanation of CHF through various conditions at the current stage of research, since there still remain some ambiguous points even in several key phases of this phenomenon. There are several models differentiating the mechanism of CHF between the pool and the forced flow boiling, and they explain the CHF mechanism in forced flow boiling by assuming that some sort of viscous boundary layer flows over the heated surface.
General features of CHF of forced convection boiling in vertical concentric annuli with a uniformly heated rod and zero inlet subcooling
1981, International Journal of Heat and Mass Transfer
A graphical method is employed to give a generalized bird's-eye view of the existing data for critical heat flux (CHF) in internally and uniformly heated vertical annuli with zero inlet subcooling. 301 data points collected from 25 sources are used for this purpose, including 7 different fluids (water, R-12, R-114, acetone, toluene, monoisopropyl-biphenyl, and sodium), axial length of heated rod from 0.0762 to 8.84 m, outer diameter of heated rod from 0.00500 to 0.0964 m, inner diameter of unheated shroud tube from 0.0127 to 0.101 m, and vapor/liquid density ratio from 0.0000580 to 0.160.
On emploie une méthode graphique pour donner une vue d'ensemble des données existantes pour le flux de chaleur critique (CHF) dans des espaces annulaires, verticaux, uniformément chauffés intérieurement et avec un sous-refroidissement nul à l'entrée. 301 données sont tirées de 25 sources et ils concernent 7 fluides différents (eau, R-12, R-114, acétone, toluène, monoisopropylbiphényl et sodium), des longueurs chauffées de 0,0762-8,84 m, des diamètres externes de barre chauffée entre 0,005 et 0,0964 m, des diamètres internes de tube enveloppant entre 0,0127 et 0,101 m, et des rapports vapeur/liquide depuis 0,000058 jusqu'à 0,160.
Um einen allgemeinen Überblick über die vorhandenen Daten für die kritische Wärmestromdichte in von innen gleichmäβig beheizten senkrechten Ringspalten ohne Unterkühlung am Eintritt zu erhalten, wurde eine grafische Methode angewandt. Aus 25 Quellen wurden 301 Angaben zu diesem Zweck zusammengetragen. Diese umfassen: sieben verschiedene Fluide (Wasser, R12, R114, Aceton, Toluen, Monoisopropylbiphenyl und Natrium), axiale Längen des beheizten Stabes von 0,0762 bis 8,84m, äuβere Durchmesser des beheizten Stabes von 0,005 bis 0,0964m, innere Durchmesser des äuβeren Mantelrohres von 0,0127 bis 0,101 m und Dampf/Flüssigkeits-Verhältnisse von 0,000058 bis 0,16.
qIcпo ызyя гpaфичecкий мeтoд. пpoвeдeн oбзop имeющичcя лaнньч нo кpиичecкoмy тeплoвoмy пoтoкy в. paвнoмepнo нaгpeвeмыч изнyгpн кoлзьиeвыч кaнaaлaч пpи oтcyтcтвии нeдoгpeвa нa. вчoдe c этoй пeлью былa взятa 301 тoчкa иa 25 пyбликaпий для 7 зидкocтeй (вoдa. R-12. R-14,. aцeтгoн, тoлyoл. мoиoизoпpoпил-бифeнил нaтpнй). Длинa пaгpeвaeмoгo cepдeчникa пo ocи cocтaвлялa 0,0762 8,84 м. нapyзный лиaмeтp cepдeчникa измeнялcя oт 0.00500 лo 0,0964 м. впyтpeнний лиaмeтp пeиaгpeвaeмoй тpyбь измeнялcя oт 0.0127 лo 0,101м a oгнoщeниe coдepзaний пapa и зидкocти измeнялocь в пpeдeлaч oт 0.0000580 лo 0.160.
CFD modelling of annular two-phase flow and heat transfer
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Burn-out, circumferential film flow distribution and pressure drop for an eccentric annulus with heated rod

Abstract

Air—water climbing film flow in an eccentric annulus

U.K.A.E.A., Report No. AERE-R5787

Two-phase flow and heat transfer in multirod geometries