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Title: Numerical simulation of supercritical heat transfer under severe axial density gradient in a narrow vertical tube

A number of computational works have been performed so far for the simulation of heat transfer in a supercritical fluid. The simulations, however, faced a lot of difficulties when heat transfer deteriorates due either to buoyancy or by acceleration. When the bulk temperature approaches the pseudo-critical temperature the fluid experiences a severe axial density gradient on top of a severe radial one. Earlier numerical calculations showed, without exception, unrealistic over-predictions, as soon as the bulk temperature exceeded the pseudo-critical temperature. The over-predictions might have been resulted from an inapplicability of widely-used turbulence models. One of the major causes for the difficulties may probably be an assumption of a constant turbulent Prandtl number. Recent research, both numerical and experimental, indicates that the turbulent Prandtl number is never a constant when the gradient of physical properties is significant. This paper describes the applicability of a variable turbulent Prandtl number to the numerical simulation of heat transfer in supercritical fluids flowing in narrow vertical tubes. (authors)
Authors:
; ;  [1]
  1. Korea Atomic Energy Research Inst., 1045 Daedeokdaero, Daejeon (Korea, Republic of)
Publication Date:
OSTI Identifier:
22105945
Resource Type:
Conference
Resource Relation:
Conference: ICAPP '12: 2012 International Congress on Advances in Nuclear Power Plants, Chicago, IL (United States), 24-28 Jun 2012; Other Information: Country of input: France; 37 refs.; Related Information: In: Proceedings of the 2012 International Congress on Advances in Nuclear Power Plants - ICAPP '12| 2799 p.
Publisher:
American Nuclear Society - ANS; La Grange Park (United States)
Research Org:
American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 22 GENERAL STUDIES OF NUCLEAR REACTORS; COMPUTERIZED SIMULATION; CRITICAL TEMPERATURE; DENSITY; FLUIDS; HEAT TRANSFER; PRANDTL NUMBER; TUBES; TURBULENT FLOW