Enhancement of heat transfer in a typical pressurized water reactor by different mixing vanes on spacer grids

Nematollahi, Mohammadreza; Nazifi, Mohammad

doi:10.1016/j.enconman.2007.12.016

Cited by 33 publications

(15 citation statements)

References 4 publications

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“…Great efforts have been taken to improve the performance of the rod-bundle lattice, such as adding the wire-wrapped spacers outside of rods (Hamman and Berry, 2010) or mixing vanes on spacer grids (Nematollahi and Nazifi, 2008;Navarroa and Santos, 2011). Meanwhile, there is another mechanism which also has significant influence on the flow and heat transfer characteristic of the rod-bundle lattice.…”

Section: Introductionmentioning

confidence: 98%

Numerical simulation of heat transfer and friction in non-uniform wall roughness lattice with different roughness element shapes

Xiao

Chen

Yan

2015

Annals of Nuclear Energy

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Section: Introductionmentioning

confidence: 98%

Numerical simulation of heat transfer and friction in non-uniform wall roughness lattice with different roughness element shapes

Xiao

Chen

Yan

2015

Annals of Nuclear Energy

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“…Holloway's [11] research showed the importance of choosing appropriate turbulence models and the shear stress transport (SST) k-ω turbulence model obtained a successful simulation of a low Reynolds number area near the wall. Nematollahi [12] evaluated the effects of flow and heat transfer intensity with different mixing vanes on spacer grids. The vanes were divided into split vane, ripped open shape, trumpet shape, and split trumpet shape.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on the Flow Characteristics in a 17 × 17 Full-Scale Fuel Assembly

et al. 2020

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In a previous study, several computational fluid dynamics (CFD) simulations of fuel assembly thermal-hydraulic problems were presented that contained fewer fuel rods, such as 3 × 3 and 5 × 5, due to limited computer capacity. However, a typical AFA-3G fuel assembly consists of 17 × 17 rods. The pressure drop levels and flow details in the whole fuel assembly, and even in the pressurized water reactor (PWR), are not available. Hence, an appropriate CFD method for a full-scale 17 × 17 fuel assembly was the focus of this study. The spacer grids with mixing vanes, springs, and dimples were considered. The polyhedral and extruded mesh was generated using Star-CCM+ software and the total mesh number was about 200 million. The axial and lateral velocity distribution in the sub-channels was investigated. The pressure distribution downstream of different spacer grids were also obtained. As a result, an appropriate method for full-scale rod bundle simulations was obtained. The CFD analysis of thermal-hydraulic problems in a reactor coolant system can be widely conducted by using real-size fuel assembly models.

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“…The mixing vanes grid spacers are one of the most widely used groups of heat transfer enhancement tools to boost turbulent flow and heat transfer in the PWR fuel subchannels. The grid spacers and mixing vanes have since 1970's undergone gradual development in order to improve their performance [1][2][3][4][5][6][7][8][9][10][11][12][13]. Preliminary experimental analysis of PWR grid spacer was undertaken by Rehme [1][2][3] that resulted in correlations for several grid spacers without mixing vanes.…”

Section: Introductionmentioning

confidence: 99%

“…Numerous studies have showed [13,28,30,31] that the addition of mixing vane on the grid spacer generates more anisotropic axial swirling pattern compared against the standard grid spacer. Nematollahi and Nazifi [13] showed that the standard split mixing vane is expected to significantly enhance the overall heat transfer of a nuclear fuel assembly by 9.82% with a reasonable increase in the pumping cost. Toth and Aszodi [16] emphasized that the grid spacer has an important bearing on the crossflows, axial velocity and outlet temperature distribution in subchannels.…”

Section: Introductionmentioning

confidence: 99%

Computational fluid dynamic simulation of swirl flow in hexagonal rod bundle geometry by split mixing vane grid spacers

Nazififard

2019

THERM SCI

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Heat transfer and pressure drop are numerically investigated for turbulent flows through a hexagonal fuel rod bundle. For the purpose of numerical analysis, the geometric and boundary conditions were taken from the VVER-1000. Since VVER-1000 does not have mixing vane on the grid spacer of the fuel assembly, split mixing vane is designed to boost turbulent flow and heat transfer in the rod bundle subchannels. The computational domain including two grid spacers extend from 100 × D h upstream of the first grid spacer to 250 × D h downstream of the second grid spacer. The steady-state form of the RANS, mass, energy and turbulence equations was discretized and solved using ANSYS-CFX. The standard k-ε model is employed to simulate turbulence. The results show a considerable increase in the average heat transfer to ~10 × D h downstream of the grid spacer using the mixing vane on the grid spacer of VVER type reactor. As expected, the pressure loss through the grid spacer also increased slightly with the mixing vanes.

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Enhancement of heat transfer in a typical pressurized water reactor by different mixing vanes on spacer grids

Cited by 33 publications

References 4 publications

Numerical simulation of heat transfer and friction in non-uniform wall roughness lattice with different roughness element shapes

Numerical simulation of heat transfer and friction in non-uniform wall roughness lattice with different roughness element shapes

Numerical Investigation on the Flow Characteristics in a 17 × 17 Full-Scale Fuel Assembly

Computational fluid dynamic simulation of swirl flow in hexagonal rod bundle geometry by split mixing vane grid spacers

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