Benchmarking Computational Fluid Dynamics for Application to PWR Fuel

2002 ◽  
Author(s):  
L. D. Smith ◽  
M. E. Conner ◽  
B. Liu ◽  
B. Dzodzo ◽  
D. V. Paramonov ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Temperature Fields ◽  
Cfd Modeling ◽  
Spacer Grid ◽  
Cfd Models ◽  
Computational Mesh ◽  
Transfer Testing ◽  
Visualization Techniques

The present study demonstrates a process used to develop confidence in Computational Fluid Dynamics (CFD) as a tool to investigate flow and temperature distributions in a PWR fuel bundle. The velocity and temperature fields produced by a mixing spacer grid of a PWR fuel assembly are quite complex. Before using CFD to evaluate these flow fields, a rigorous benchmarking effort should be performed to ensure that reasonable results are obtained. Westinghouse has developed a method to quantitatively benchmark CFD tools against data at conditions representative of the PWR. Several measurements in a 5×5 rod bundle were performed. Lateral flowfield testing employed visualization techniques and Particle Image Velocimetry (PIV). Heat transfer testing involved measurements of the single-phase heat transfer coefficient downstream of the spacer grid. These test results were used to compare with CFD predictions. Among the parameters optimized in the CFD models based on this comparison with data include computational mesh, turbulence model, and boundary conditions. As an outcome of this effort, a methodology was developed for CFD modeling that provides confidence in the numerical results.

scholarly journals Computational Fluid Dynamics Modeling of Liver Radioembolization: A Review

2021 ◽  
Author(s):  
Jorge Aramburu ◽  
Raúl Antón ◽  
Macarena Rodríguez-Fraile ◽  
Bruno Sangro ◽  
José Ignacio Bilbao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Point Of View ◽  
Cfd Modeling ◽  
Dynamics Modeling ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Modeling ◽  
Cfd Models ◽  
Computational Fluid Dynamics Cfd ◽  
Intraarterial Therapy

AbstractYttrium-90 radioembolization (RE) is a widely used transcatheter intraarterial therapy for patients with unresectable liver cancer. In the last decade, computer simulations of hepatic artery hemodynamics during RE have been performed with the aim of better understanding and improving the therapy. In this review, we introduce the concept of computational fluid dynamics (CFD) modeling with a clinical perspective and we review the CFD models used to study RE from the fluid mechanics point of view. Finally, we show what CFD simulations have taught us about the hemodynamics during RE, the current capabilities of CFD simulations of RE, and we suggest some future perspectives.

Computational fluid dynamics and experimental analysis of the heat transfer in a room with a roof solar chimney

2021 ◽  
pp. 1-26
Author(s):  
Adolfo Vazquez ◽  
Jose MA Navarro ◽  
Jesus Hinojosa ◽  
Dr. Jesús Xamán
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Heat Flux ◽  
Computational Fluid Dynamics ◽  
Experimental Analysis ◽  
Vertical Wall ◽  
Temperature Fields ◽  
Heated Wall ◽  
Transfer Coefficients ◽  
Solar Chimney

Abstract This study reports a numerical-experimental analysis of heat transfer and airflow in a scaled room with a heated wall coupled with a double-channel vertical roof solar chimney. For the experimental part, a parametric study was performed in the thermal system, considering different values of heat flux supplied to a vertical wall of the scaled room (75 and 150 W/m2) and the absorber surface of the solar chimney (151 and 667 W/m2). Experimental temperature profiles were obtained at six different depths and heights, and experimental heat transfer coefficients were computed for both heated surfaces. The renormalization group k-e turbulence model was evaluated against experimental data using computational fluid dynamics software. With the validated model, the effect of the heated wall and solar chimney on temperature fields, flow patterns, and heat transfer convective coefficients are presented and discussed. The cases with heat flux on the heated wall of the scaled room produce the biggest air changes per hour (ACH), being 30.1, 31.2, and 23.4 ACH for cases 1 to 3 respectively, while cases with no heated wall produce fewer ACH (11.72 and 12.28 for case 4 and 5). The comparison between cases with and without heat flux on one vertical wall but the same solar chimney heat flux shows that the ACH increases between 154 % and 156% respectively.

Computational Fluid Dynamics Simulation of Flow-Mixing and Heat Transfer in 4 × 4 Rod Bundle With a Twist-Vane Spacer Grid

2019 ◽  
Vol 5 (4) ◽  
Author(s):  
Ganesh Lal Kumawat ◽  
Anuj Kumar Kansal ◽  
Naresh Kumar Maheshwari ◽  
Avaneesh Sharma
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Atomic Energy ◽  
Cfd Simulations ◽  
Spacer Grid ◽  
Fuel Rod ◽  
Rod Bundle ◽  
Flow Mixing ◽  
Computational Fluid Dynamics Cfd

The clearance between fuel rods is maintained by spacer grid or helical wire wrap. Thermal-hydraulic characteristics inside fuel rod bundle are strongly influenced by the spacer grid geometry and the bundle pitch-to-diameter (P/D) ratio. This includes the maximum fuel temperature, critical heat flux, as well as pressure drop through the fuel bundle. An understanding of the detailed structure of flow mixing and heat transfer in a fuel rod bundle geometry is therefore an important aspect of reactor core design, both in terms of the reactor's safe and reliable operation, and with regard to optimum power extraction. In this study, computational fluid dynamics (CFD) simulations are performed to investigate isothermal turbulent flow mixing and heat transfer behavior in 4 × 4 rod bundle with twist-vane spacer grid with P/D ratio of 1.35. This work is carried out under International Atomic Energy Agency (IAEA) co-ordinated research project titled as “Application of Computational Fluid Dynamics (CFD) Codes for Nuclear Power Plant Design.” CFD simulations are performed using open source CFD code OpenFOAM. Numerical results are compared with experimental data from Korea Atomic Energy Research Institute (KAERI) and found to be in good agreement.

Turbine Endwall Contouring for the Reduction of Endwall Heat Transfer Using the Ice Formation Method Along With Computational Fluid Dynamics

2014 ◽  
Author(s):  
Sven Winkler ◽  
Kristian Haase ◽  
Janosch Brucker ◽  
Bernhard Weigand
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Ice Formation ◽  
Formation Method ◽  
Endwall Contouring ◽  
Dynamics Simulations

Turbine endwall contouring has become very popular for optimizing gas turbines. Increasingly often, three-dimensional contours are applied between turbine airfoils to reduce aerodynamic losses or heat transfer rates. These reductions directly result from the shaping of such contours which modifies the flow and thermal field in their vicinity. Here, we report on the development of novel endwall contours for a generic low pressure vane profile to reduce endwall heat transfer. Using the flat endwall as baseline, different endwall contours were created using the Ice Formation Method. This natural approach imposes only minimum restrictions on the design space and is therefore considered advantageous to other optimization procedures. The created contours were subsequently analyzed by Computational Fluid Dynamics simulations. Results showed that all created contours reduced endwall heat transfer compared to the baseline, the highest reduction being 7% in terms of the averaged endwall Stanton number. For this endwall contour, we performed detailed analyses of the numerically predicted flow and temperature fields to indicate how the shaping of this contour affects the flow and temperature fields and hence causes the observed heat transfer reduction.

Predicting Hydrodynamic and Heat Transfer Effects of Sparger Geometry and Placement Within a Column Photobioreactor Using Computational Fluid Dynamics

2014 ◽  
Vol 11 (3) ◽  
Author(s):  
Ghazi S. Bari ◽  
Taylor N. Suess ◽  
Gary A. Anderson ◽  
Stephen P. Gent
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Porous Membrane ◽  
Flow Patterns ◽  
Transfer Effects ◽  
Eulerian Approach ◽  
Cfd Models ◽  
Computational Fluid Dynamics Cfd ◽  
Heat Transfer Effects

This research investigates the effects of the sparger on flow patterns and heat transfer within a column photobioreactor (PBR) using computational fluid dynamics (CFD). This study compares two types of spargers: a porous membrane, which occupies the entire floor of the reactor, and a single sparger, which is located along the centerline of the PBR floor. The PBR is modeled using the Lagrangian–Eulerian approach. The objective of this research is to predict the performance of PBRs using CFD models, which can be used to improve the design of PBRs used to grow microalgae that are used to produce biofuels and bioproducts.

Numerical simulation of conductive heat transfer in canned celery stew and retort program adjustment by computational fluid dynamics (CFD)

2020 ◽  
Vol 16 (9) ◽  
Author(s):  
Arezoo Berenjforoush Azar ◽  
Yousef Ramezan ◽  
Morteza Khashehchi
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Thermal Processing ◽  
Conductive Heat Transfer ◽  
Heating Zone ◽  
Conductive Heat ◽  
Cfd Models ◽  
Computational Fluid Dynamics Cfd ◽  
Slowest Heating Zone

AbstractIn this study, conductive heat transfer was investigated during sterilization in the canned celery stew. A computational fluid dynamics CFD model was developed and validated to predict the temperature profiles and determine the slowest heating zone (SHZ) during the thermal processing. The temperature profile was obtained and recorded experimentally at a point where the coldest thermal point was expected. CFD models were validated against experimental data. The results of the study showed that the SHZ was located at the geometric center of the containers (x = 5.00, y = 1.42, z = 6.75 cm), and the temperature reached 119.5 °C. Root mean square error (RMSE) was calculated and showed a good fit between both methods (RMSE = 1.03). The container geometrical center F0 was estimated to be 13.19 min. For optimization of the process, according to the stew ingredients, especially meat, F0 was about 8 min. Thus, the required holding time was decreased by 5.19 min, and the retort setting was readjusted.

Computational Fluid Dynamics Analysis of the Transient Cooling of the Boiling Surface at Bubble Departure

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Giovanni Giustini ◽  
S. P. Walker ◽  
Yohei Sato ◽  
Bojan Niceno
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Heat Flux ◽  
Computational Fluid Dynamics ◽  
Mechanistic Modeling ◽  
Heated Wall ◽  
Cfd Modeling ◽  
Scale Modeling ◽  
Flux Partitioning ◽  
Computational Fluid Dynamics Analysis

Component-scale computational fluid dynamics (CFD) modeling of boiling via heat flux partitioning relies upon empirical and semimechanistic representations of the modes of heat transfer believed to be important. One such mode, “quenching,” refers to the bringing of cool water to the vicinity of the heated wall to refill the volume occupied by a departing vapor bubble. This is modeled in classical heat flux partitioning approaches using a semimechanistic treatment based on idealized transient heat conduction into liquid from a perfectly conducting substrate. In this paper, we apply a modern interface tracking CFD approach to simulate steam bubble growth and departure, in an attempt to assess mechanistically (within the limitations of the CFD model) the single-phase heat transfer associated with bubble departure. This is in the spirit of one of the main motivations for such mechanistic modeling, the development of insight, and the provision of quantification, to improve the necessarily more empirical component scale modeling. The computations indicate that the long-standing “quench” model used in essentially all heat flux partitioning treatments embodies a significant overestimate of this part of the heat transfer, by a factor of perhaps ∼30. It is of course the case that the collection of individual models in heat flux partitioning treatments has been refined and tuned in aggregate, and it is not particularly surprising that an individual submodel is not numerically correct. In practice, there is much cancelation between inaccuracies in the various submodels, which in aggregate perform surprisingly well. We suggest ways in which this more soundly based quantification of “quenching heat transfer” might be taken into account in component scale modeling.

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