Turbulent Transverse Plane PIV Measurements on a Wire-Wrapped 61-Pin Hexagonal Fuel Bundle

2018 ◽  
Author(s):  
Nolan E. Goth ◽  
Philip Jones ◽  
Thien D. Nguyen ◽  
Rodolfo Vaghetto ◽  
Yassin Hassan
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Fast Reactor ◽  
Measurement Techniques ◽  
Transverse Plane ◽  
Index Of Refraction ◽  
Plane Flow ◽  
Sodium Fast Reactor ◽  
Fuel Bundle

This study recaps the experimental effort to characterize a transverse plane flow field in a tightly-packed, 61-pin, wire-wrapped, hexagonal fuel bundle prototypical for a sodium fast reactor. The motive was to produce high spatiotemporal experimental data for computational fluid dynamics turbulence model validation. The matched-index-of-refraction and laser-based optical measurement techniques were utilized on an isothermal experimental flow facility. Measurements were performed on a transverse plane perpendicular to the axial flow. Fluid flow in the three types of subchannels (corner, exterior, and interior) were quantified. All measurements have been performed at a bundle-averaged Reynolds number of approximately 10,400. Results include flow statistics such as ensemble-averaged velocity, root-mean-square fluctuating velocity, and Reynolds stress. Of interest was the flow behavior around the restriction caused by the wire spacer and hexagonal duct wall, where recirculation regions formed. Regions of maximum and minimum momentum transfer coincided with regions of maximum and minimum fluctuations. These regions highlight locations of maximum and minimum cooling of the fuel pins. The experimental data will be used to benchmark computational fluid dynamics simulations of the sodium fast reactor fuel bundle using Reynolds-averaged Navier Stokes and large-eddy simulation turbulence modeling methods.

scholarly journals A comparison of computational fluid dynamics predicted initial liquid penetration using rate of injection profiles generated using two different measurement techniques

2017 ◽  
Vol 20 (2) ◽  
pp. 226-235 ◽  
Author(s):  
Haiwen Ge ◽  
Jaclyn E Johnson ◽  
Hari Krishnamoorthy ◽  
Seong-Young Lee ◽  
Jeffrey D Naber ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Momentum Flux ◽  
Measurement Techniques ◽  
Liquid Penetration ◽  
Flux Method ◽  
Computational Fluid Dynamics Simulations ◽  
Bulk Charge ◽  
Dynamics Simulations

The rate of injection profile is a key parameter describing the fuel injection process for diesel injection. It is also an essential input parameter for computational fluid dynamics simulations of spray flows. In the present work, rate of injection profiles of a multi-hole diesel injector were measured using the Zeuch method and the momentum flux method. The rate of injection profiles measured by the momentum flux method had a faster rise in rate of injection during the initial ramp-up phase than with the Zeuch method. The measured rate of injection profiles were applied in three-dimensional computational fluid dynamics simulations of diesel sprays under non-vaporizing and vaporizing conditions with sweeps in injection pressure, bulk charge gas density, and bulk charge gas temperature. Analytical results were compared against experimental data for liquid penetration generated under those conditions. Computational fluid dynamics results with the rate of injection profile measured by the Zeuch method under-predict liquid penetration during the initial ramp-up phase, while computational fluid dynamics results with the rate of injection profiles measured by the momentum flux method showed much better agreement with the experimental data of liquid length and penetration. This suggests that current computational fluid dynamics spray models may be able to more accurately model transient liquid penetration when using the velocity profile developed from momentum flux measurements. Further study is needed to evaluate how computational fluid dynamics predictions of combustion and emissions of affected when using these two rate of injection profiles.

scholarly journals Modelling of working processes of non-contact oil free vacuum pumps by computational fluid dynamics (CFD) methods

2021 ◽  
Vol 2059 (1) ◽  
pp. 012003
Author(s):  
A Burmistrov ◽  
A Raykov ◽  
S Salikeev ◽  
E Kapustin
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Mathematical Models ◽  
Cfd Models ◽  
Ansys Cfx ◽  
Sst Turbulence Model ◽  
Computational Fluid Dynamics Cfd ◽  
Dynamic Meshing ◽  
Comparison With Experimental Data

Abstract Numerical mathematical models of non-contact oil free scroll, Roots and screw vacuum pumps are developed. Modelling was carried out with the help of software CFD ANSYS-CFX and program TwinMesh for dynamic meshing. Pumping characteristics of non-contact pumps in viscous flow with the help of SST-turbulence model were calculated for varying rotors profiles, clearances, and rotating speeds. Comparison with experimental data verified adequacy of developed CFD models.

Computational Fluid Dynamics Techniques for Flows in Lapple Cyclone Separator

2005 ◽  
Vol 498-499 ◽  
pp. 179-185
Author(s):  
A.F. Lacerda ◽  
Luiz Gustavo Martins Vieira ◽  
A.M. Nascimento ◽  
S.D. Nascimento ◽  
João Jorge Ribeiro Damasceno ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Turbulent Flow ◽  
Reynolds Stress ◽  
Cyclone Separator ◽  
Two Dimensional ◽  
Stress Components ◽  
Computational Fluid Dynamics Cfd

A two-dimensional fluidynamics model for turbulent flow of gas in cyclones is used to evaluate the importance of the anisotropic of the Reynolds stress components. This study presents consisted in to simulate through computational fluid dynamics (CFD) package the operation of the Lapple cyclone. Yields of velocity obtained starting from a model anisotropic of the Reynolds stress are compared with experimental data of the literature, as form of validating the results obtained through the use of the Computational fluid dynamics (Fluent). The experimental data of the axial and swirl velocities validate numeric results obtained by the model.

Computational Fluid Dynamics Modeling of Mixed Convection Flows in Building Enclosures

2013 ◽  
Author(s):  
Alexander Kayne ◽  
Ramesh Agarwal
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Mixed Convection ◽  
Turbulence Model ◽  
Numerical Algorithm ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Flow And Heat Transfer

In recent years Computational Fluid Dynamics (CFD) simulations are increasingly used to model the air circulation and temperature environment inside the rooms of residential and office buildings to gain insight into the relative energy consumptions of various HVAC systems for cooling/heating for climate control and thermal comfort. This requires accurate simulation of turbulent flow and heat transfer for various types of ventilation systems using the Reynolds-Averaged Navier-Stokes (RANS) equations of fluid dynamics. Large Eddy Simulation (LES) or Direct Numerical Simulation (DNS) of Navier-Stokes equations is computationally intensive and expensive for simulations of this kind. As a result, vast majority of CFD simulations employ RANS equations in conjunction with a turbulence model. In order to assess the modeling requirements (mesh, numerical algorithm, turbulence model etc.) for accurate simulations, it is critical to validate the calculations against the experimental data. For this purpose, we use three well known benchmark validation cases, one for natural convection in 2D closed vertical cavity, second for forced convection in a 2D rectangular cavity and the third for mixed convection in a 2D square cavity. The simulations are performed on a number of meshes of different density using a number of turbulence models. It is found that k-epsilon two-equation turbulence model with a second-order algorithm on a reasonable mesh gives the best results. This information is then used to determine the modeling requirements (mesh, numerical algorithm, turbulence model etc.) for flows in 3D enclosures with different ventilation systems. In particular two cases are considered for which the experimental data is available. These cases are (1) air flow and heat transfer in a naturally ventilated room and (2) airflow and temperature distribution in an atrium. Good agreement with the experimental data and computations of other investigators is obtained.

Detailed Analysis of the Wake Structure of a Straight-Blade H-Darrieus Wind Turbine by Means of Wind Tunnel Experiments and Computational Fluid Dynamics Simulations

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Alessandro Bianchini ◽  
Francesco Balduzzi ◽  
Giovanni Ferrara ◽  
Lorenzo Ferrari ◽  
Giacomo Persico ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Wind Turbines ◽  
Large Scale ◽  
Vertical Axis ◽  
Performance Estimation ◽  
Small Scale ◽  
Dynamics Simulations

Darrieus vertical axis wind turbines (VAWTs) have been recently identified as the most promising solution for new types of applications, such as small-scale installations in complex terrains or offshore large floating platforms. To improve their efficiencies further and make them competitive with those of conventional horizontal axis wind turbines, a more in depth understanding of the physical phenomena that govern the aerodynamics past a rotating Darrieus turbine is needed. Within this context, computational fluid dynamics (CFD) can play a fundamental role, since it represents the only model able to provide a detailed and comprehensive representation of the flow. Due to the complexity of similar simulations, however, the possibility of having reliable and detailed experimental data to be used as validation test cases is pivotal to tune the numerical tools. In this study, a two-dimensional (2D) unsteady Reynolds-averaged Navier–Stokes (U-RANS) computational model was applied to analyze the wake characteristics on the midplane of a small-size H-shaped Darrieus VAWT. The turbine was tested in a large-scale, open-jet wind tunnel, including both performance and wake measurements. Thanks to the availability of such a unique set of experimental data, systematic comparisons between simulations and experiments were carried out for analyzing the structure of the wake and correlating the main macrostructures of the flow to the local aerodynamic features of the airfoils in cycloidal motion. In general, good agreement on the turbine performance estimation was constantly appreciated.

Hydrodynamic Analysis of Macroalgae Local Model Using Computational Fluid Dynamics

2020 ◽  
Author(s):  
Ming Chen ◽  
Solomon C. Yim ◽  
Daniel Cox ◽  
Zhaoqing Yang ◽  
Thomas Mumford
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Current Model ◽  
Global Scale ◽  
Local Scale ◽  
Constant Current ◽  
Scale Model ◽  
Effective Diameter ◽  
Hydrodynamic Coefficients

Abstract In this article, a local scale, fully nonlinear coupled fluid-structural interaction (FSI) sugar kelp model has been developed using a computational fluid dynamics (CFD) method. In this model, to be consistent with available experimental data, the sugar kelp is approximated as elongated rectangles with smoothed isosceles triangles at the ends and a single kelp model with one end fixed in a channel with constant current model is developed. Several different current speeds are simulated, and the resulting drag forces and calculated drag coefficients are validated by comparison with experimental data from the literature. In a previous study, a global scale model was developed using a computational structural dynamics (CSD) method to simulate macroalgae farming system and guide the system configuration design. In the global scale model, the hydrodynamic forces are calculated using Morison’s equation and the kinematics and dynamics of the sugar kelp are simplified and the group of kelps attached to the long line is modeled as a slender structure with the same length and an effective diameter such that the volumes are consistent with the real physical system. This simplified model matches the weight and buoyancy but adjusting the hydrodynamic properties when the general hydrodynamic coefficients are employed. Therefore, optimal hydrodynamic coefficients used in global scale model were determined to obtain the hydrodynamic force more accurately. The validated local scale model is then be applied to determine the hydrodynamic coefficients of the simplified sugar kelp model for global dynamic analysis.

Inlet Losses in Counterflow Wet-Cooling Towers

2001 ◽  
Vol 123 (2) ◽  
pp. 460-464 ◽  
Author(s):  
E. de Villiers ◽  
D. G. Kro¨ger
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Numerical Model ◽  
Loss Coefficient ◽  
Cooling Towers ◽  
Empirical Correlations ◽  
Dependent Variables ◽  
Loss Coefficients

The inlet loss coefficients for dry, isotropically packed, circular and rectangular counterflow cooling towers are determined experimentally and empirical correlations are formulated to fit this data. Computational fluid dynamics is used to investigate the dependence of the inlet loss coefficient on the rain zone characteristics. The rain zone generally dampens the inlet loss, but the coupling is indirect and involves a large number of dependent variables. The numerical model is validated by means of experimental data for dry towers and it is found that the degree of accuracy achieved for circular towers exceeds that for rectangular towers. Consequently, the correlation derived to predict this occurrence for circular towers can be applied more confidently than its rectangular counterpart.

Computational Fluid Dynamics Modeling of Gas–Liquid Cylindrical Cyclones, Geometrical Analysis

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Juan Carlos Berrio ◽  
Eduardo Pereyra ◽  
Nicolas Ratkovich
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Cfd Modeling ◽  
Nozzle Geometry ◽  
Geometrical Parameters ◽  
Experimental Setup ◽  
Dynamics Modeling ◽  
Two Phase ◽  
Mean Square Errors

The gas–liquid cylindrical cyclone (GLCC) is a widely used alternative for gas–liquid conventional separation. Besides its maturity, the effect of some geometrical parameters over its performance is not fully understood. The main objective of this study is to use computational fluid dynamics (CFD) modeling in order to evaluate the effect of geometrical modifications in the reduction of liquid carry over (LCO) and gas carry under (GCU). Simulations for two-phase flow were carried out under zero net liquid flow, and the average liquid holdup was compared with Kanshio (Kanshio, S., 2015, “Multiphase Flow in Pipe Cyclonic Separator,” Ph.D. thesis, Cranfield University, Cranfield, UK) obtaining root-mean-square errors around 13% between CFD and experimental data. An experimental setup, in which LCO data were acquired, was built in order to validate a CFD model that includes both phases entering to the GLCC. An average discrepancy below 6% was obtained by comparing simulations with experimental data. Once the model was validated, five geometrical variables were tested with CFD. The considered variables correspond to the inlet configuration (location and inclination angle), the effect of dual inlet, and nozzle geometry (diameter and area reduction). Based on the results, the best configuration corresponds to an angle of 27 deg, inlet location 10 cm above the center, a dual inlet with 20 cm of spacing between both legs, a nozzle of 3.5 cm of diameter, and a volute inlet of 15% of pipe area. The combination of these options in the same geometry reduced LCO by 98% with respect to the original case of the experimental setup. Finally, the swirling decay was studied with CFD showing that liquid has a greater impact than the gas flowrate.

CFD Validation for a Marine Propeller Using an Unstructured Mesh Based RANS Method

2003 ◽  
Author(s):  
Shin Hyung Rhee ◽  
Shitalkumar Joshi
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Tip Vortex ◽  
Computational Results ◽  
Marine Propeller ◽  
Experimental Conditions ◽  
Cfd Validation ◽  
Local Flow ◽  
Thrust And Torque

Results of computational fluid dynamics validation for flow around a marine propeller are presented. Computations were performed for various advance ratios following experimental conditions. The objectives of the study are to propose and verify a hybrid mesh generation strategy, and to validate computational results against experimental data with advanced computational fluid dynamics tools. Computational results for both global and local flow quantities are discussed and compared with experimental data. The predicted thrust and torque are in good agreement with the measured values. The pressure distribution and pathlines on and around the blade surface well reproduce the physics of highly skewed marine propeller flow with tip vortex. The circumferentially averaged velocity components compare well with the measured values, while the velocity and turbulence quantities in the highly concentrated tip vortex region are under-predicted. The overall results suggest that the present approach is practicable for actual propeller design procedures.

A Study of Aerodynamics Force Evaluation of Horizontal Axis Wind Turbine (HAWT) Blade Using 2D and 3D Comparison

2015 ◽  
Author(s):  
Nazia Binte Munir ◽  
Kyoungsoo Lee ◽  
Ziaul Huque ◽  
Raghava R. Kommalapati
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Blade Surface ◽  
Aerodynamic Forces ◽  
Horizontal Axis Wind Turbine ◽  
Computational Fluid Dynamics Cfd ◽  
Experimental Values ◽  
Nrel Phase Vi

The main purpose of the paper is to use Computational Fluid Dynamics (CFD) in 3-D analysis of aerodynamic forces of a Horizontal Axis Wind Turbine (HAWT) blade and compare the 3-D results with the 2-D experimental results. The National Renewable Energy Laboratory (NREL) Phase VI wind blade profile is used as a model for the analysis. The results are compared with the experimental data obtained by NREL at NASA Ames Research Center for the NREL Phase VI wind turbine blade. The aerodynamic forces are evaluated using 3-D Computational Fluid Dynamics (CFD) simulation. The commercial ANSYS CFX and parameterized 3-D CAD model of NREL Phase VI are used for the analysis. The Shear Stress Transport (SST) Gamma-Theta turbulence model and 0-degree yaw angle condition are adopted for CFD analysis. For the case study seven varying wind speeds (5 m/s, 7 m/s, 10 m/s, 13 m/s, 15 m/s, 20 m/s, 25 m/s) with constant blade rotational speed (72 rpm) are considered. To evaluate the 3-D aerodynamic effect sectional pressure coefficient (Cp) and integrated forces about primary axis such as normal, tangential, thrust and torque are evaluated for each of the seven wind speed cases and compared with the NREL experimental values. The numerical difference of values on wind blade surface between this study and 3-D results of NREL wind tunnel test are found negligible. The paper represents an important comparison between the 3-D lift & drag coefficient with the NREL 2-D experimental data. The results shows that though the current study is in good agreement with NREL 3-D experimental values there is large deviation between the NREL 2-D experimental data and current 3-D study which suggests that in case of 3-D analysis of aerodynamic force of blade surface it is better to use NREL 3-D values instead of 2-D experimental values.

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