Two-group phase distribution characteristics for air-water flow in 5  ×  5 vertical rod bundle channel with mixing vane spacer grids

2021 ◽  
Vol 176 ◽  
pp. 121444
Author(s):  
Quan-Yao Ren ◽  
Liang-Ming Pan ◽  
Zengping Pu ◽  
Fawen Zhu ◽  
Hui He
Keyword(s):  
Water Flow ◽  
Phase Distribution ◽  
Distribution Characteristics ◽  
Spacer Grids ◽  
Rod Bundle

scholarly journals Numerical and experimental investigation of the water flow through PWR spacer grids

2021 ◽  
Vol 8 (3A) ◽  
Author(s):  
Higor Fabiano Pereira de Castro ◽  
Guilherme Augusto Moura Vidal ◽  
Tiago Augusto Santiago Vieira ◽  
Vitor Vasconcelos Araújo Silva ◽  
Daniel De Almeida Magalhães Campolina ◽  
...  
Keyword(s):  
Water Flow ◽  
Technology Development ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Spacer Grids ◽  
Rod Bundle ◽  
Ansys Cfx ◽  
Flow Through ◽  
Belo Horizonte ◽  
Main Components

Spacer grids are one of main components of a Pressurized Water Reactor (PWR) fuel assembly. They are able to improve heat transfer from rod bundles to the water flow by increasing turbulence and mixture of this flow. On the other hand the pressure drop increases because spacer grids. Experimental and Computational Fluid Dynamics (CFD) analysis have been used to understand how spacer grids affect the water flow. This analysis is important to improve spacer grids thermal-hydraulic performance. This paper aims to investigate numerically and experimentally the water flow through PWR spacer grids. The numerical and experimental procedures have been developed for a 5x5 rod bundle with spacer grids at the Nuclear Technology Development Center (CDTN) in Belo Horizonte, Brazil. At CDTN, measurements of the velocity components are acquired with a 2D LDV (Laser Doppler Velocimetry) system and the numerical results are obtained using ANSYS CFX code. The measurements are obtained at one height downstream from a spacer grid and compared to CFD simulations for a flow rate at Reynolds number of 5.4x104 . Results show good agreement between both methodologies. The great repeatability and low experimental uncertainty evaluated (< 1.24%) in this work can be used to validate other CFD codes.

PHASE DISTRIBUTION CHARACTERISTICS OF CAP BUBBLY FLOW IN 5×5 ROD BUNDLES WITH MIXING VANE SPACER GRIDS

2019 ◽  
Vol 2019.27 (0) ◽  
pp. 1994
Author(s):  
Quan-yao Ren ◽  
Liang-ming Pan ◽  
Wen-xiong Zhou ◽  
Zeng-ping Pu ◽  
Mei-yin Zheng ◽  
...  
Keyword(s):  
Phase Distribution ◽  
Bubbly Flow ◽  
Distribution Characteristics ◽  
Rod Bundles ◽  
Spacer Grids

Strong Flux Pinning Caused by Phase Distribution Characteristics in (Ba,K)Fe2As2 Films

2018 ◽  
Vol 28 (3) ◽  
pp. 1-5
Author(s):  
Myeong jun Oh ◽  
Hyeong Jun Lim ◽  
Min Su Seo ◽  
S. Y. Park ◽  
Won Nam Kang ◽  
...  
Keyword(s):  
Flux Pinning ◽  
Phase Distribution ◽  
Distribution Characteristics

Numerical Flow Simulation of Spacer Grids With Mixing Vanes in a 5 × 5 PWR Rod Bundle

2009 ◽  
Author(s):  
Moyse´s Alberto Navarro ◽  
Andre´ Augusto Campagnole dos Santos
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Pressure Loss ◽  
Considerable Increase ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Spacer Grid ◽  
Spacer Grids ◽  
Rod Bundle ◽  
Vane Angle

The spacer grids exert great influence on the thermal hydraulic performance of the PWR fuel assembly. The presence of the spacers has two antagonistic effects on the core: an increase of pressure drop due to constriction on the coolant flow area and increase of the local heat transfer downstream the grids caused by enhanced coolant mixing. The mixing vanes, present in most of the spacer grid designs, cause a cross and swirl flow between and in the subchannels, enhancing even more the local heat transfer at the cost of more pressure loss. Due to this important hydrodynamic feature the spacer grids are often improved aiming to obtain an optimal commitment between pressure drop and enhanced heat transfer. In the present work, the fluid dynamic performance downstream a 5 × 5 rod bundle with spacer grids is analyzed with a commercial CFD code (CFX 11.0). Eleven different split vane spacer grids with angles from 16° to 36° and a spacer without vanes were evaluated. The computational domain extends from ∼10 Dh upstream to ∼50 Dh downstream the spacer grids. The standard k-ε turbulence model with scalable wall functions and the total energy model were used in the simulations. The results show a considerable increase of the average Nusselt number and secondary mixing with the angle of the vane up to ∼20 Dh downstream the spacer, reducing greatly the influence of the vane angle beyond this region. As expected, the pressure loss through the spacer grid also showed considerable increase with the vane angle.

Experimental study of laminar mixed convection in a rod bundle with mixing vane spacer grids

2017 ◽  
Vol 312 ◽  
pp. 99-105 ◽  
Author(s):  
Lokanath Mohanta ◽  
Fan-Bill Cheung ◽  
Stephen M. Bajorek ◽  
Kirk Tien ◽  
Chris L. Hoxie
Keyword(s):  
Experimental Study ◽  
Mixed Convection ◽  
Spacer Grids ◽  
Rod Bundle ◽  
Laminar Mixed Convection

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

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 397 ◽  
Author(s):  
Zihao Tian ◽  
Lixin Yang ◽  
Shuang Han ◽  
Xiaofei Yuan ◽  
Hongyan Lu ◽  
...  
Keyword(s):  
Fuel Assembly ◽  
Flow Characteristics ◽  
Full Scale ◽  
Pressurized Water Reactor ◽  
Lateral Velocity ◽  
Pressurized Water ◽  
Spacer Grids ◽  
Rod Bundle ◽  
Real Size ◽  
Cfd Method

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.

Turbulent Flow Through Spacer Grids in Rod Bundles

1998 ◽  
Vol 120 (4) ◽  
pp. 786-791 ◽  
Author(s):  
Sun Kyu Yang ◽  
Moon Ki Chung
Keyword(s):  
Turbulent Flow ◽  
Laser Doppler Velocimetry ◽  
Hydraulic Characteristics ◽  
Rod Bundles ◽  
Spacer Grid ◽  
Spacer Grids ◽  
Rod Bundle ◽  
Turbulence Decay ◽  
Skewness Factor ◽  
Flow Through

The effects of the spacer grids with mixing vanes in rod bundles on the turbulent structure were investigated experimentally. The detailed hydraulic characteristics in subchannels of a 5 × 5 rod bundle with mixing spacer grids were measured upstream and downstream of the spacer grid by using a one component LDV (Laser Doppler Velocimetry). Axial velocity and turbulent intensity, skewness factor, and flatness factor were measured. The turbulence decay behind spacer grids was obtained from measured data. The trend of turbulence decay behaves in a similar way as turbulent flow through mesh grids or screens. Pressure drop measurements were also performed to evaluate the loss coefficient for the spacer grid and the friction factor for a rod bundle.

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