Influence of Spacer Elements on Flow Distribution and Heat Transfer in Experimental Models of Fuel Assemblies

Experimental investigations of thermal hydraulic properties of coolant flow in experimental models of fuel assemblies (FA) were performed. FA models with 7, 19 and 37 pins in hexagonal arrangement were used as test sections. Friction loss coefficients of smooth rod bundles are presented and compared. Hydraulic resistance of spacing grids with different geometry is discussed. Comparison of obtained data with correlations of Rehme and Idelchik is carried out. Averaged heat transfer dependences on distance from spacer grid top end are presented and compared with different dependences. Experimental results for coolant velocity distribution in subchannels of experimental models were obtained using both Pitot pipe technique and laser Doppler annemometry (LDA). It was shown that a strong disturbance of the flow just behind the spacer grid is present. The flow stabilization occurs at relatively small distances from the spacer elements.

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Study on heat transfer behavior in rod bundles with spacer grid

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2017.12.121 ◽

2018 ◽

Vol 120 ◽

pp. 1065-1075 ◽

Cited By ~ 8

Author(s):

Da Liu ◽

Hanyang Gu

Keyword(s):

Heat Transfer ◽

Rod Bundles ◽

Spacer Grid ◽

Heat Transfer Behavior ◽

Transfer Behavior

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Influence of Spacer Grid Outer Strap on Fuel Assembly Thermal Hydraulic Performance

Science and Technology of Nuclear Installations ◽

10.1155/2014/602062 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Jingwen Yan ◽

Yuxiang Zhang ◽

Baowen Yang ◽

Weicai Li ◽

Yuemin Zhou

Keyword(s):

Fuel Assembly ◽

Cross Flow ◽

Flow Distribution ◽

Hydraulic Performance ◽

Computational Domain ◽

Spacer Grid ◽

Typical Structure ◽

Mixing Performance ◽

Ansys Cfx ◽

Fuel Assemblies

The outer strap as a typical structure of a spacer grid enhances the mechanical strength, decreases hang-up susceptibility, and also influences thermal hydraulic performance, for example, pressure loss, mixing performance, and flow distribution. In the present study, a typical grid spacer with different outer strap designs is adopted to investigate the influence of outer strap design on fuel assembly thermal hydraulic performance by using a commercial computational fluid dynamics (CFD) code, ANSYS CFX, and a subchannel analysis code, FLICA. To simulate the outer straps’ influence between fuel assemblies downstream, four quarter-bundles from neighboring fuel assemblies are constructed to form the computational domain. The results show that the outer strap design has a major impact on cross-flow between fuel assemblies and temperature distribution within the fuel assembly.

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Evaluation and development of heat transfer model for supercritical water flowing in 2 × 2 rod bundles with spacer grid

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2020.120702 ◽

2021 ◽

Vol 165 ◽

pp. 120702

Author(s):

Meng Zhao ◽

Fangnian Wang ◽

Aurelian Florin Badea

Keyword(s):

Heat Transfer ◽

Supercritical Water ◽

Heat Transfer Model ◽

Transfer Model ◽

Rod Bundles ◽

Spacer Grid

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CFD Analysis of the Flow in Crud-Coated Nuclear Rod Bundles

Volume 4: Radiation Protection and Nuclear Technology Applications; Fuel Cycle, Radioactive Waste Management and Decommissioning; Computational Fluid Dynamics (CFD) and Coupled Codes; Reactor Physics and Transport Theory ◽

10.1115/icone22-30788 ◽

2014 ◽

Author(s):

Nicolas Cinosi ◽

Simon P. Walker ◽

Mike Bluck ◽

Raad I. Issa

Keyword(s):

Heat Transfer ◽

Mass Flow Rate ◽

Flow Rate ◽

Flow Distribution ◽

Normal Operation ◽

Cfd Analysis ◽

Rod Bundles ◽

Ideal Case ◽

Rans Models ◽

The Ideal

This paper presents a methodology to assess the effects of crud surface roughnesses on the normal operation of a PWR reactor. A CFD methodology based on the use of RANS models and the implementation of roughness embedded in STAR-CCM+ CFD code has been developed and applied. A typical PWR reactor case is investigated in details. Results show how the presence of crudded rough rods induces a modification of the flow distribution as compared to the ideal case with clean smooth rods. Notably, these modifications reflect a reduction of the mass flow rate, which in turn has a deteriorating consequence on the efficiency of the fuel-to-coolant heat transfer.

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