Colombo, M orcid.org/0000-0002-4335-4250, Cammi, A, Guédon, GR et al. (2 more authors) (2015) CFD study of an air–water flow inside helically coiled pipes. Progress in Nuclear Energy, 85. pp. 462-472. ISSN 0149-1970
Abstract
CFD is used to study an air–water mixture flowing inside helically coiled pipes, being at the moment considered for the Steam Generators (SGs) of different nuclear reactor projects of Generation III+ and Generation IV. The two-phase mixture is described through the Eulerian–Eulerian model and the adiabatic flow is simulated through the ANSYS FLUENT code. A twofold objective is pursued. On the one hand, obtaining an accurate estimation of physical quantities such as the frictional pressure drop and the void fraction. In this regard, CFD simulations can provide accurate predictions without being limited to a particular range of system parameters, which often constricts the application of empirical correlations. On the other hand, a better understanding of the role of the centrifugal force field and its effect on the two-phase flow field and the phase distributions is pursued.
The effect of the centrifugal force field introduced by the geometry is characterized. Water is pushed by the centrifugal force towards the outer pipe wall, whereas air accumulates in the inner region of the pipe. The maximum of the mixture velocity is therefore shifted towards the inner pipe wall, as the air flows much faster than the water, having a considerably lower density. The flow field, as for the single-phase flow, is characterized by flow recirculation and vortices. Quantitatively, the simulation results are validated against the experimental data of Akagawa et al. (1971) for the void fraction and the frictional pressure drop. The relatively simple model of momentum interfacial transfer allows obtaining a very good agreement for the average void fraction and a satisfactory estimation of the frictional pressure drop and, at the same time, limits the computational cost of the simulations. Effects of changes in the diameter of the dispersed phase are described, as its value strongly affects the degree of interaction between the phases. In addition, a more precise treatment of the near wall region other than wall function results in a better definition of the liquid film at the wall, although an overestimation of the frictional pressure drop is obtained.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2015 Elsevier Ltd. All rights reserved. This is an author produced version of an article, published in Progress in Nuclear Energy. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Helical pipes; CFD study; Eulerian multiphase model; Frictional pressure drop; Void fraction; Experimental data |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 13 Mar 2020 15:28 |
Last Modified: | 14 Mar 2020 09:03 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.pnucene.2015.07.006 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:157490 |