Two and Three-Dimensional Simulations of Enhanced Heat Transfer in Nuclear Fuel Rod Bundles

2009 ◽  
Author(s):  
Leo A. Carrilho ◽  
Jamil Khan ◽  
Michael E. Conner ◽  
Abdel Mandour ◽  
Milorad B. Dzodzo
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Turbulent Flow ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Element Model ◽  
Sensitivity Analyses ◽  
Artificial Roughness ◽  
Pressurized Water ◽  
Fuel Rod

The effects of artificial roughness for the purpose of thermal performance improvement in pressurized water nuclear reactors are investigated. The artificial roughness consists of two-dimensional ribs parallel to the turbulent flow. The fuel rod bundle subchannel is preliminarily modeled as an annulus using the finite element method in ANSYS/FLOTRAN. The Navier-Stokes equations are solved from the SST (Shear Stress Transport) turbulence model for the simulated annulus thermal-flow. The analyses are performed for ribs dimensions and pitch provided by published previous work. It is found that, heat transfer and differential pressure have similar behavior with highest heat transfer occurring at the reattachment point. The finite element model describes well the characteristics of turbulent flow in smooth and rough rod when compared to previous semi-empirical models. Next paper extends the analysis by comparing numerical results with experimental test data and sensitivity analyses for different roughness configurations.

Enhancement of Heat Transfer Performance in Nuclear Fuel Rod Using Nanofluids and Surface Roughness Technique

2015 ◽  
Author(s):  
Kang Liu ◽  
Titan C. Paul ◽  
Leo A. Carrilho ◽  
Jamil A. Khan
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Nuclear Fuel ◽  
Three Dimensional ◽  
Pressurized Water ◽  
Bulk Fluid ◽  
Fuel Rod ◽  
Dimensional Surface

The experimental investigations were carried out of a pressurized water nuclear reactor (PWR) with enhanced surface using different concentration (0.5 and 2.0 vol%) of ZnO/DI-water based nanofluids as a coolant. The experimental setup consisted of a flow loop with a nuclear fuel rod section that was heated by electrical current. The fuel rod surfaces were termed as two-dimensional surface roughness (square transverse ribbed surface) and three-dimensional surface roughness (diamond shaped blocks). The variation in temperature of nuclear fuel rod was measured along the length of a specified section. Heat transfer coefficient was calculated by measuring heat flux and temperature differences between surface and bulk fluid. The experimental results of nanofluids were compared with the coolant as a DI-water data. The maximum heat transfer coefficient enhancement was achieved 33% at Re = 1.15 × 105 for fuel rod with three-dimensional surface roughness using 2.0 vol% nanofluids compared to DI-water.

scholarly journals Finite Element Analysis of Turbulent Flows Using LES and Dynamic Subgrid-Scale Models in Complex Geometries

2011 ◽  
Vol 2011 ◽  
pp. 1-20 ◽  
Author(s):  
Wang Wenquan ◽  
Zhang Lixiang ◽  
Yan Yan ◽  
Guo Yakun
Keyword(s):  
Finite Element ◽  
Turbulent Flow ◽  
Turbulent Flows ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Turbulent Channel Flow ◽  
Francis Turbine ◽  
Complex Geometries ◽  
Subgrid Scale ◽  
Element Analysis

An innovative computational model is presented for the large eddy simulation (LES) of multidimensional unsteady turbulent flow problems in complex geometries. The main objectives of this research are to know more about the structure of turbulent flows, to identify their three-dimensional characteristic, and to study physical effects due to complex fluid flow. The filtered Navier-Stokes equations are used to simulate large scales; however, they are supplemented by dynamic subgrid-scale (DSGS) models to simulate the energy transfer from large scales toward subgrid-scales, where this energy will be dissipated by molecular viscosity. Based on the Taylor-Galerkin schemes for the convection-diffusion problems, this model is implemented in a three-dimensional finite element code using a three-step finite element method (FEM). Turbulent channel flow and flow over a backward-facing step are considered as a benchmark for validating the methodology by comparing with the direct numerical simulation (DNS) results or experimental data. Also, qualitative and quantitative aspects of three-dimensional complex turbulent flow in a strong 3D blade passage of a Francis turbine are analyzed.

Discussion on Finite Element Model for Three Dimensional Rolling Process Analysis

2014 ◽  
Vol 496-500 ◽  
pp. 452-455
Author(s):  
Chi Chih Shen
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Finite Element ◽  
Theoretical Model ◽  
Process Analysis ◽  
Three Dimensional ◽  
Element Model ◽  
Rolling Process ◽  
Strip Rolling ◽  
Rigid Matrix

A three dimensional numerical simulation model of metal rolling formation is developed from the theoretical model. In this theoretical model, the two variables of element deformation and temperature variation are placed in a variable matrix. The thermal elastic plastic rigid matrix and heat transfer rigid matrix are placed in the same expansion rigid matrix. Furthermore, the numerical simulation analytical model developed in this paper was used to simulate aluminum strip rolling.

Numerical Simulation of Three Dimensional Turbulent Flow and Heat Transfer Within a Multi-Ribbed Cylindrical Duct

1991 ◽  
Author(s):  
C. Taylor ◽  
J. Y. Xia ◽  
J. O. Medwell ◽  
W. D. Morris
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Fluid Model ◽  
Three Dimensional ◽  
Local Variation ◽  
Element Model ◽  
Enhancement Of Heat Transfer ◽  
Transfer Rates ◽  
Flow And Heat Transfer ◽  
Solid Walls

Turbulent flow and heat transfer within stationary and rotating cylindrical ribbed ducts is simulated using a finite element model. The transfer of heat from the solid walls into the fluid is effected using a coupled solid/fluid model and details of the rapid local variation of local Nusselt, especially adjacent to the ribs, is predicted. The enhancement of heat transfer, when compared with heat transfer within a smooth rotating duct, due to the incorporation of ribs is demonstrated. The numerically determined bulk heat transfer rates are also compared with experimental results.

Investigation the influence of spacer yarns orientation angle on the thermal behavior of 3D textile reinforced concrete (TRC)

2021 ◽  
pp. 095440622110473
Author(s):  
Sayyed Behzad Abdellahi ◽  
Sayyed Mahdi Hejazi ◽  
Hossein Hasani
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Thermal Behavior ◽  
Three Dimensional ◽  
Orientation Angle ◽  
Element Model ◽  
Textile Reinforced Concrete ◽  
Cementitious Matrix

Thermal behavior such as heat transfer is an important parameter for construction composites. Three-dimensional textile reinforced concrete (TRC) is one of the construction composites which is recently being used in the building industry. Therefore, in this study, the thermal behavior of three different TRC samples was investigated by a heat transfer test using an infrared method. The cementitious matrix was reinforced by 3D fabric with three different spacer yarn orientation angles. The cementitious matrix was fabricated by cement and waste stone powder. The TRC sample was put on the hot plate of the heat transfer apparatus and the temperature variations of the top surface of the sample were obtained. According to the test results, increasing the orientation angle of spacer yarns leads to a decrease in the thermal conductivity of the TRC sample and reduces heat transfer. On the other hand, a theoretical model was used to calculate the thermal conductivity and resistance coefficients of sandwich samples. Furthermore, a 3D finite element model was used to predict the heat transfer of TRC specimens. A unit cell of the TRC model was created in Abaqus software and finite element (FE) analysis was carried on a created model. Thermal conductivity and thermal resistance of samples according to FE results were calculated and compared with experimental results. FE results showed good agreement with the experimental data.

scholarly journals Sensitivity Analysis of a Nuclear Reactor System Finite Element Model

2018 ◽  
Author(s):  
Gregory A. Banyay ◽  
Stephen D. Smith ◽  
Jason S. Young
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Surrogate Model ◽  
Computational Design ◽  
Element Model ◽  
Sensitivity Analyses ◽  
Physical Parameters ◽  
Loading Conditions ◽  
Pressurized Water

The structures associated with the nuclear steam supply system (NSSS) of a pressurized water reactor (PWR) warrant evaluation of various non-stationary loading conditions which could occur over the life of a nuclear power plant. These loading conditions include those associated with a loss of coolant accident and seismic event. The dynamic structural system is represented by a finite element model consisting of significant epistemic and aleatory uncertainties in the physical parameters. To provide an enhanced understanding of the influence of these uncertainties on model results, a sensitivity analysis is performed. This work demonstrates the construction of a computational design of experiment which runs the finite element model a sufficient number of times to train and verify a unique aggregate surrogate model. Adaptive sampling is employed in order to reduce the overall computational burden. The surrogate model is then used to perform both global and local sensitivity analyses.

Immersed volume method for solving natural convection, conduction and radiation of a hat‐shaped disk inside a 3D enclosure

2012 ◽  
Vol 22 (6) ◽  
pp. 718-741 ◽  
Author(s):  
E. Hachem ◽  
H. Digonnet ◽  
E. Massoni ◽  
T. Coupez
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Thermal Properties ◽  
Natural Convection ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Content Type ◽  
Stabilized Finite Element ◽  
Level Set Function ◽  
Volume Method

PurposeThe purpose of this paper is to present an immersed volume method that accounts for solid conductive bodies (hat‐shaped disk) in calculation of time‐dependent, three‐dimensional, conjugate heat transfer and fluid flow.Design/methodology/approachThe incompressible Navier‐Stokes equations and the heat transfer equations are discretized using a stabilized finite element method. The interface of the immersed disk is defined and rendered by the zero isovalues of a level set function. This signed distance function allows turning different thermal properties of each component into homogeneous parameters and it is coupled to a direct anisotropic mesh adaptation process enhancing the interface representation. A monolithic approach is used to solve a single set of equations for both fluid and solid with different thermal properties.FindingsIn the proposed immersion technique, only a single grid for both air and solid is considered, thus, only one equation with different thermal properties is solved. The sharp discontinuity of the material properties was captured by an anisotropic refined solid‐fluid interface. The robustness of the method to compute the flow and heat transfer with large materials properties differences is demonstrated using stabilized finite element formulations. Results are assessed by comparing the predictions with the experimental data.Originality/valueThe proposed method demonstrates the capability of the model to simulate an unsteady three‐dimensional heat transfer flow of natural convection, conduction and radiation in a cubic enclosure with the presence of a conduction body. A previous knowledge of the heat transfer coefficients between the disk and the fluid is no longer required. The heat exchange at the interface is solved and dealt with naturally.

Investigation of Thermal-Hydraulic Field in the Annular Channel Around the Heated Wall of the Fuel Rod

2013 ◽  
Author(s):  
D. Lavicka ◽  
Y. Knapp ◽  
J. Polansky
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Turbulent Flow ◽  
Annular Flow ◽  
Annular Channel ◽  
Flow Channel ◽  
Heated Wall ◽  
Two Phase ◽  
Pressurized Water ◽  
Fuel Rod

Experimental measurement serves for investigation of temperature field in the annular flow channel along the heated wall of the fuel rod. Research focuses on the issue of heat transfer into the coolant at two-phase turbulent flow. Two-phase turbulent flow contains a large quantity of bubbles and, with heat transfer; it represents a very complex process. The annular flow depends on the application of spacers that affect the flow and temperature field in the flow channel at the fuel rod model. The fuel rod represents the fuel cluster in nuclear pressurized water reactor (PWR) of the VVER type.

scholarly journals Model Updating and Aeroelastic Correlation of a Scaled Wind Tunnel Model for Active Flutter Suppression Test

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 334
Author(s):  
Domenico Di Leone ◽  
Francesco Lo Balbo ◽  
Alessandro De Gaspari ◽  
Sergio Ricci
Keyword(s):  
Finite Element ◽  
Wind Tunnel ◽  
Model Updating ◽  
Three Dimensional ◽  
Wind Tunnel Test ◽  
Ground Vibration ◽  
Element Model ◽  
Sensitivity Analyses ◽  
Flutter Suppression ◽  
Active Flutter Suppression

This article presents a modal correlation and update carried out on an aeroelastic wind tunnel demonstrator representing a conventional passenger transport aircraft. The aim of this work is the setup of a corresponding numerical model that is able to capture the flutter characteristics of a scaled aeroelastic model designed to investigate and experimentally validate active flutter suppression technologies. The work described in this paper includes different finite element modeling strategies, the results of the ground vibration test, and finally the strategies adopted for modal updating. The result of the activities is a three-dimensional hybrid finite element model that is well representative of the actual aeroelastic behavior identified during the wind tunnel test campaign and that is capable of predicting the flutter boundary with an error of 1.2%. This model will be used to develop active flutter suppression controllers, as well as to perform the sensitivity analyses necessary to investigate their robustness.

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