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Science and Technology of Nuclear Installations
Volume 2014, Article ID 635651, 15 pages
http://dx.doi.org/10.1155/2014/635651
Research Article

CFD Turbulence Study of PWR Spacer-Grids in a Rod Bundle

1Institute for Energy Engineering, Universitat Politècnica de València, Camino de Vera, s/n, 46022 Valencia, Spain
2Department of Mechanical Engineering and Construction, Universitat Jaume I, Avenida Sos Baynat, s/n, 12071 Castellón de la Plana, Spain

Received 7 October 2013; Accepted 13 February 2014; Published 30 June 2014

Academic Editor: Bao-Wen Yang

Copyright © 2014 C. Peña-Monferrer et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Nuclear fuel bundles include spacers essentially for mechanical stability and to influence the flow dynamics and heat transfer phenomena along the fuel rods. This work presents the analysis of the turbulence effects of a split-type and swirl-type spacer-grid geometries on single phase in a PWR (pressurized water reactor) rod bundle. Various computational fluid dynamics (CFD) calculations have been performed and the results validated with the experiments of the OECD/NEA-KAERI rod bundle CFD blind benchmark exercise on turbulent mixing in a rod bundle with spacers at the MATiS-H facility. Simulation of turbulent phenomena downstream of the spacer-grid presents high complexity issues; a wide range of length scales are present in the domain increasing the difficulty of defining in detail the transient nature of turbulent flow with ordinary turbulence models. This paper contains a complete description of the procedure to obtain a validated CFD model for the simulation of the spacer-grids. Calculations were performed with the commercial code ANSYS CFX using large eddy simulation (LES) turbulence model and the CFD modeling procedure validated by comparison with measurements to determine their suitability in the prediction of the turbulence phenomena.