5X5 Rod Bundle Flow Field Measurements Downstream a PWR Spacer Grid

Higor Fabiano Pereira de Castro; Vitor Vasconcelos Araújo Silva; Andre Augusto Campagnole dos Santos; Maria Auxiliadora Fortini Veloso

doi:10.15392/bjrs.v8i1.724

Authors

Higor Fabiano Pereira de Castro Universidade Federal de Minas Gerais
Vitor Vasconcelos Araújo Silva
Andre Augusto Campagnole dos Santos
Maria Auxiliadora Fortini Veloso

DOI:

https://doi.org/10.15392/bjrs.v8i1.724

Keywords:

(fuel assembly, spacer grids, PWR, LDV).

Abstract

The spacer grids are structures present in nuclear fuel assembly of Pressurized Water Reactors (PWR). They play an important structural role and also assist in heat removal through the assembly by promoting increased turbulence of the flow. Understanding the flow dynamics downstream the spacer grid is paramount for fuel element design and analysis. This paper presents water flow velocity profiles measurements downstream a spacer grid in a 5x5 rod bundle test rig with the objective of highlighting important fluid dynamic behavior near the grid and supplying data for CFD simulation validation. These velocity profiles were obtained at two different heights downstream the spacer grid using a LDV (Laser Doppler Velocimetry) through the top of test rig. The turbulence intensities and patterns of the swirl and cross flow were evaluated. The tests were conducted for Reynolds numbers ranging from 1.8x104 to 5.4x104. This experimental research was carried out in thermohydraulics laboratory of Nuclear Technology Development Center – CDTN. Results show great repeatability and low uncertainties (< 1.24 %). Details of the flow field show how the mixture and turbulence induced by the spacer grid quickly decays downstream the spacer grid. It is shown that the developed methodology can supply high resolution low uncertainty results that can be used for validation of CFD simulations.

Views: 129
PDF Downloads: 184

Downloads

Download data is not yet available.

References

CHANG, S. K.; KIM, S.; SONG, C. H. Turbulent mixing in a rod bundle with vaned spacer grids. Nuclear Engineering and Design, v. 279, p. 19–36, 2014.

XIONG, J.; YU, Y.; YU, N.; FU, X.; WANG, H.; CHENG, X.; YANG, W. Laser Doppler Measurement and CFD Validation in 3x3 Bundle Flow. Nuclear Engineering and Design. v. 270, p. 396-403, 2014.

CONNER M. E.; DOMINGUEZ O; ELVIS E.; HASSAN Y. A. Hydraulic benchmark data for PWR mixing vane grid. In: INTERNATIONAL TOPICAL MEETING ON NUCLEAR REACTOR THERMAL HYDRAULICS, 2011, Toronto. Annals… Toronto: Canadian Nuclear Society, 2011. p. 25-30.

YLÖNEN, A. T. High-resolution flow structure measurements in a rod bundle. Thesis, at the Department of Mechanical and Process Engineering at the ETH, Zürich, Switzerland, 2013.

NAVARRO M. A.; SANTOS, A. A. C. Numerical Evaluation of Flow through a 5x5 PWR Rod Bundle: Effect of the Vane Arrangement in a Spacer Grid. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, 2009, Rio de Janeiro, Annals… Rio de Janeiro: Comissão Nacional de Energia Nuclear, 2009.

KAROUTAS Z.; GU C.; SHOLIN, B. 3-D Flow analyses for design of Nuclear Fuel Spacer. In: INTERNATIONAL TOPICAL MEETING ON NUCLEAR REACTOR THERMAL HYDRAULICS, 1995, Saratoga Springs. Annals… Saratoga Springs: United States Nuclear Regulatory Commission, 1995. p. 3153-3174.

BSA Flow Software. BSA Flow Software Version 4.10 Instalation & User’s Guide. Dantec Dynamics A/S, Denmark, 2006.

ISO – International Organization of Standardization. Measurements of fluid flow by means of pressure differential devices. ISO 5167-1, Geneva: ISO 1991. 33p.

CHUN, T. H.; OH, D S. A pressure drop model for spacer grids with and without flow mixing vanes. Journal of Nuclear Science and Technology, v. 35, p. 508-510, 1998.

IN, W. K.; OH, D. S.; CHUN, T. H. Empirical and Computational Pressure Drop Correlations for Pressurized Water Reactors Fuel Spacer Grids. Nuclear Technology, v. 139, p. 7279, 2002.

IN W. K.; SHIN C. K.; OH D. S.; CHUN T. H. Experimental Observation and CFD Prediction of Flow Mixing in a Rod Bundle with Mixing-vane Spacer Grid. In: PACIFIC SYMPOSIUM ON FLOW VISUALIZATION AND IMAGE PROCESSING, 2015, Naples, Annals… Naples: Dep. Of Industrial Engineering University of Naples Frederico II, 2015. p. 15-18.