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Title: Steady-state observations and theoretical modeling of critical heat flux phenomena on a downward facing hemispherical surface

Abstract

Steady-state boiling experiments were performed in the SBLB test facility to observe the two-phase boundary layer flow behavior on the outer surface of a heated hemispherical vessel near the critical heat flux (CHF) limit and to measure the spatial variation of the local CHF along the vessel outer surface. Based upon the flow observations, an advanced hydrodynamic CHF model was developed. The model considers the existence of a micro-layer underneath an elongated vapor slug on the downward facing curved heating surface. The micro-layer is treated as a thin liquid film with numerous micro-vapor jets penetrating through it. The micro-jets have the characteristic size dictated by Helmholtz instability. Local dryout is considered to occur when the supply of fresh liquid from the two phase boundary layer to the micro-layer is not sufficient to prevent depletion of the liquid film by boiling. A boundary layer analysis, treating the two-phase motion as a separated flow, is performed to determine the liquid supply rate and thus the local critical heat flux. The model provides a clear physical explanation for the spatial variation of the CHF observed in the SBLB experiments and for the weak dependence of the CHF data on the physical size ofmore » the vessel.« less

Authors:
;  [1]
  1. Pennsylvania State Univ., University Park, PA (United States)
Publication Date:
Research Org.:
US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Office of Nuclear Regulatory Research; Brookhaven National Lab. (BNL), Upton, NY (United States)
OSTI Identifier:
269690
Report Number(s):
NUREG/CP-0149-Vol.2; CONF-9510156-Vol.2
ON: TI96007985; CNN: Contract NRC-04-93-061; TRN: 96:016796
Resource Type:
Conference
Resource Relation:
Conference: 23. water reactor safety information meeting, Bethesda, MD (United States), 23-25 Oct 1995; Other Information: PBD: Mar 1996; Related Information: Is Part Of Twenty-third water reactor safety information meeting: Volume 2, Human factors research; Advanced I and C hardware and software; Severe accident research; Probabilistic risk assessment topics; Individual plant examination: Proceedings; Monteleone, S. [comp.] [Brookhaven National Lab., Upton, NY (United States)]; PB: 514 p.
Country of Publication:
United States
Language:
English
Subject:
22 NUCLEAR REACTOR TECHNOLOGY; 42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; CORIUM; COOLING; BOUNDARY LAYERS; FILM BOILING; SURFACES; REACTOR VESSELS; BENCH-SCALE EXPERIMENTS; CRITICAL HEAT FLUX; WATER COOLED REACTORS; MATHEMATICAL MODELS

Citation Formats

Cheung, F B, and Haddad, K H. Steady-state observations and theoretical modeling of critical heat flux phenomena on a downward facing hemispherical surface. United States: N. p., 1996. Web.
Cheung, F B, & Haddad, K H. Steady-state observations and theoretical modeling of critical heat flux phenomena on a downward facing hemispherical surface. United States.
Cheung, F B, and Haddad, K H. 1996. "Steady-state observations and theoretical modeling of critical heat flux phenomena on a downward facing hemispherical surface". United States. https://www.osti.gov/servlets/purl/269690.
@article{osti_269690,
title = {Steady-state observations and theoretical modeling of critical heat flux phenomena on a downward facing hemispherical surface},
author = {Cheung, F B and Haddad, K H},
abstractNote = {Steady-state boiling experiments were performed in the SBLB test facility to observe the two-phase boundary layer flow behavior on the outer surface of a heated hemispherical vessel near the critical heat flux (CHF) limit and to measure the spatial variation of the local CHF along the vessel outer surface. Based upon the flow observations, an advanced hydrodynamic CHF model was developed. The model considers the existence of a micro-layer underneath an elongated vapor slug on the downward facing curved heating surface. The micro-layer is treated as a thin liquid film with numerous micro-vapor jets penetrating through it. The micro-jets have the characteristic size dictated by Helmholtz instability. Local dryout is considered to occur when the supply of fresh liquid from the two phase boundary layer to the micro-layer is not sufficient to prevent depletion of the liquid film by boiling. A boundary layer analysis, treating the two-phase motion as a separated flow, is performed to determine the liquid supply rate and thus the local critical heat flux. The model provides a clear physical explanation for the spatial variation of the CHF observed in the SBLB experiments and for the weak dependence of the CHF data on the physical size of the vessel.},
doi = {},
url = {https://www.osti.gov/biblio/269690}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Mar 01 00:00:00 EST 1996},
month = {Fri Mar 01 00:00:00 EST 1996}
}

Conference:
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