Modelling of complex boron dilution transients in PWRs—Validation of CFD simulation with ANSYS CFX against the ROCOM E2.3 experiment

2021 ◽  
Vol 372 ◽  
pp. 110938
Author(s):  
A. Grahn ◽  
E. Diaz Pescador ◽  
S. Kliem ◽  
F. Schäfer ◽  
T. Höhne
Keyword(s):  
Cfd Simulation ◽  
Ansys Cfx ◽  
Boron Dilution

Load Characteristics of Steel and Concrete Tubular Members Under Jet Fire: An Experimental and Numerical Study

2010 ◽  
Author(s):  
Jeong Hyo Park ◽  
Bong Ju Kim ◽  
Jung Kwan Seo ◽  
Jae Sung Jeong ◽  
Byung Keun Oh ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Numerical Study ◽  
Fire Load ◽  
Adiabatic Wall ◽  
Fire Engineering ◽  
Ansys Cfx ◽  
Design Values ◽  
Computational Fluid Dynamics Cfd ◽  
Load Characteristics ◽  
Set Up

The aim of this study was to evaluate the load characteristics of steel and concrete tubular members under jet fire, with the motivation to investigate the jet fire load characteristics in FPSO topsides. This paper is part of Phase II of the joint industry project on explosion and fire engineering of FPSOs (EFEF JIP) [1]. To obtain reliable load values, jet fire tests were carried out in parallel with a numerical study. Computational fluid dynamics (CFD) simulation was used to set up an adiabatic wall boundary condition for the jet fire to model the heat transfer mechanism. A concrete tubular member was tested under the assumption that there is no conduction effect from jet fire. A steel tubular member was tested and considered to transfer heat through conduction, convection, and radiation. The temperature distribution, or heat load, was analyzed at specific locations on each type of member. ANSYS CFX [2] and Kameleon FireEx [3] codes were used to obtain similar fire action in the numerical and experimental methods. The results of this study will provide a useful database to determine design values related to jet fire.

scholarly journals CFD tool application in predicting the behavior of a centrifugal fan designed by one-dimensional theory

2021 ◽  
Vol 10 (12) ◽  
pp. e412101219653
Author(s):  
Henrique Marcio Pereira Rosa ◽  
Gabriela Pereira Toledo
Keyword(s):  
Velocity Distribution ◽  
Cfd Simulation ◽  
Centrifugal Fan ◽  
Dimensional Theory ◽  
Recovery Coefficient ◽  
Characteristic Curves ◽  
One Dimensional ◽  
Ansys Cfx ◽  
Computational Fluid Dynamics Cfd ◽  
The One

Computational fluid dynamics (CFD) is the most current technology in the fluid flow study. Experimental methods for predicting the turbomachinery performance involve greater time consumption and financial resources compared to the CFD approach. The purpose of this article is to present the analysis of CFD simulation results in a centrifugal fan. The impeller was calculated using the one-dimensional theory and the volute the principle of constant angular momentum. The ANSYS-CFX software was used for the simulation. The turbulence model adopted was the SST. The simulation provided the characteristic curves, the pressure and velocity distribution, and the static and total pressure values at impeller and volute exit. An analysis of the behavior of the pressure plots, and the loss and recovery of pressure in the volute was performed. The results indicated the characteristic curves, the pressure and velocity distribution were consistent with the turbomachinery theory. The pressure values showed the static pressure at volute exit was smaller than impeller exit for some flow rate. It caused the pressure recovery coefficient negative.  This work indicated to be possible design a centrifugal fan applying the one-dimensional theory and optimize it with the CFD tool.

scholarly journals CFD Simulation of Polydispersed Bubbly Two-Phase Flow around an Obstacle

2009 ◽  
Vol 2009 ◽  
pp. 1-12 ◽  
Author(s):  
E. Krepper ◽  
P. Ruyer ◽  
M. Beyer ◽  
D. Lucas ◽  
H.-M. Prasser ◽  
...  
Keyword(s):  
Size Distribution ◽  
Cfd Simulation ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Size Distribution Function ◽  
Phase Flow ◽  
Two Phase ◽  
Ansys Cfx ◽  
Two Fluid Model ◽  
Drag And Lift

This paper concerns the model of a polydispersed bubble population in the frame of an ensemble averaged two-phase flow formulation. The ability of the moment density approach to represent bubble population size distribution within a multi-dimensional CFD code based on the two-fluid model is studied. Two different methods describing the polydispersion are presented: (i) a moment density method, developed at IRSN, to model the bubble size distribution function and (ii) a population balance method considering several different velocity fields of the gaseous phase. The first method is implemented in the Neptune_CFD code, whereas the second method is implemented in the CFD code ANSYS/CFX. Both methods consider coalescence and breakup phenomena and momentum interphase transfers related to drag and lift forces. Air-water bubbly flows in a vertical pipe with obstacle of the TOPFLOW experiments series performed at FZD are then used as simulations test cases. The numerical results, obtained with Neptune_CFD and with ANSYS/CFX, allow attesting the validity of the approaches. Perspectives concerning the improvement of the models, their validation, as well as the extension of their applicability range are discussed.

Numerical Investigation of Aerodynamic Performance of a Three-Bladed Vertical Axis Wind Turbine

2010 ◽  
Author(s):  
Alexandrina Untaroiu ◽  
Lydia R. Barker ◽  
Houston G. Wood ◽  
Robert J. Ribando ◽  
Paul E. Allaire
Keyword(s):  
Wind Turbine ◽  
Cfd Simulation ◽  
Vertical Axis ◽  
Operating Speed ◽  
University Of Virginia ◽  
Vertical Axis Wind Turbine ◽  
Start Up ◽  
Ansys Cfx ◽  
Turbine Design ◽  
The University

As a pollution free source of energy, wind is among the most popular and fastest growing forms of electricity generation in the world. Compared to their horizontal axis counterparts, vertical axis wind turbines have lagged considerably in development and implementation. The University of Virginia Rotating Machinery and Controls laboratory has undertaken a systematic review of vertical axis wind turbine design in order to address this research gap, starting with establishment of a methodology for vertical axis wind turbine simulation using ANSYS CFX. A 2D model of a recently published Durham University vertical axis wind turbine was generated. Full transient CFD simulations using the moving mesh capability available in ANSYS-CFX were run from turbine start-up to operating speed and compared with the experimental data in order to validate the technique. A scalable k-ε turbulence model transient CFD simulation has been demonstrated to accurately predict vertical axis wind turbine operating speed within 12% error using a two-dimensional structured mesh in conjunction with a carefully specified series of boundary conditions.

CFD Simulation and Wind Tunnel Investigation of a FPSO Offshore Helideck Turbulent Flow

2010 ◽  
Author(s):  
Daniel Fonseca de Carvalho e Silva ◽  
Paulo Roberto Pagot ◽  
Gilder Nader ◽  
Paulo Jose´ Saiz Jabardo
Keyword(s):  
Wind Tunnel ◽  
Particle Image ◽  
Cfd Simulation ◽  
Wind Flow ◽  
Cfd Simulations ◽  
Local Conditions ◽  
British Standard ◽  
Ansys Cfx ◽  
Tunnel Model ◽  
Image Velocimetry

The offshore helideck wind flow is usually subject to many interferences. The helideck airspace velocity and turbulence fields are important issues to promote safe helicopter take-off and landing operations. The current work brings some CFD results of a helideck wind flow 3D-field defined by the local conditions and constrained by the FPSO structure. A discussion about the chosen CFD boundary conditions is also presented. These CFD results are compared with the wind tunnel model-scale velocity and turbulence measurements. The wind tunnel measurements were performed with use of two different techniques: Particle Image Velocimetry (PIV) and Constant Temperature Anemometry (CTA). The British standard CAP437: Offshore Helideck Design Criteria is examined and suggestions are made herein. The CFD simulations were conducted using the ANSYS CFX software.

Comparison of Transient Blade Row Methods for the CFD Analysis of a High-Pressure Turbine

2014 ◽  
Author(s):  
Dirk Witteck ◽  
Derek Micallef ◽  
Ronald Mailach
Keyword(s):  
Cfd Simulation ◽  
Computational Cost ◽  
Computational Effort ◽  
Cfd Simulations ◽  
Computational Costs ◽  
Ansys Cfx ◽  
Numerical Effort ◽  
Blade Row ◽  
Flow Phenomena ◽  
Temporal Periodicity

Usually, in a turbine an uneven number of blades are selected for vane and blade rows to reduce the level of interaction forces. To consider all unsteady flow phenomena within a turbine the computation of the full annulus is required causing considerable computational cost. Transient blade row methods using few passages reduce the numerical effort significantly. Nevertheless, those approaches provide accurate results. This contribution presents three different unsteady approaches to compare the accuracy and the computational effort, using a full annulus unsteady CFD simulation as a reference. The first approach modifies the blade-to-blade ratio whereas the second method scales the circumferential flow pattern to reach spatial and temporal periodicity. Third approach is based on time-inclining method to overcome unequal blade pitches with less numerical effort. All unsteady CFD simulations are carried out for the transonic test turbine VKI BRITE EURAM using the commercial CFD solver ANSYS CFX 14.5. The resulting unsteady pressure disturbances and blade forces of the different transient blade row methods are compared to each other as well as to experimental data. Finally, the accuracy and the computational costs are discussed in more detail.

Experiment and CFD Simulation on Gas Holdup Characteristics in an Internal Loop Reactor with External Liquid Circulation

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
Chunxi Lu ◽  
Nana Qi ◽  
Kai Zhang ◽  
Jiaqi Jin ◽  
Hu Zhang
Keyword(s):  
Cfd Simulation ◽  
Gas Holdup ◽  
Gas Velocity ◽  
Loop Reactor ◽  
Internal Loop ◽  
Liquid Circulation ◽  
Liquid Phases ◽  
Ansys Cfx ◽  
Other Information ◽  
Superficial Gas Velocity

An external liquid circulation is introduced into a traditional internal loop reactor in order to improve liquid circulation and increase the interface between gas and liquid phases. The effects of superficial gas velocity and external liquid circulation velocity on local and overall gas holdups are explored experimentally and numerically in the loop section of a combined gas-liquid contactor, which consists of a liquid spray, sieve plates and an internal loop with external liquid circulation. Local gas holdup is measured experimentally by a double-sensor conductivity probe. Numerical simulations are conducted in the platform of a commercial software package, ANSYS CFX 10.0. Gas holdup and other information are obtained by solving the governing equations of mass and momentum balances for gas and liquid phases in a hybrid mesh system. Both measured and simulated results indicate that local, section-averaged, and overall gas holdups increase with an increase of the superficial gas velocity. The downcomer tube for circulating external liquid has a significant influence in the gas-distributor and the downcomer-tube action regions rather than in the upper draft-tube and the gas-liquid separation regions. Good agreement between measured and predicted data suggests that CFD simulation together with experimental investigation can be employed to develop novel gas-liquid contactors with a complex geometrical configuration.

scholarly journals CFD simulation on centrifugal pump impeller with splitter blades

2020 ◽  
Vol 24 (1) ◽  
pp. 3-7 ◽  
Author(s):  
Henrique M. P. Rosa ◽  
Bruno S. Emerick
Keyword(s):  
Centrifugal Pump ◽  
Cfd Simulation ◽  
Computational Simulations ◽  
Pump Impeller ◽  
Impeller Blade ◽  
Flow Rates ◽  
Computational Fluids Dynamics ◽  
Ansys Cfx ◽  
Computational Fluids ◽  
Centrifugal Pump Impeller

ABSTRACT The present paper aims to present the analysis and comparison of results of computational simulations using Computational Fluids Dynamics (CFD) in impellers of centrifugal pump. Three impellers were simulated: 1) original impeller, 2) original impeller with splitter blades at outlet; 3) original impeller with splitter blades at inlet. The splitters occupied 30% of the length of the main blades. They were simulated using the ANSYS-CFX software system in 1500 rpm rotational speed and at different flow rates. The turbulence model assumed was the Shear Stress Transport (SST). The results were used to build impeller blade head curves, besides the presentation of pressure distribution and streamline behaviour inside the impeller. It was verified that the insertion of the splitter blades reduced the impeller blade head, mainly the impeller with outlet splitter, whose reduction was more intense.

CFD and Experimental Analysis of Centrifugal Fans With Forward Curved Blades Used in Electric Motors

2019 ◽  
Author(s):  
S. S. Borges
Keyword(s):  
Cfd Simulation ◽  
Experimental Tests ◽  
Performance Comparison ◽  
Centrifugal Fan ◽  
Electric Motors ◽  
Cfd Simulations ◽  
Interface Models ◽  
Ansys Cfx ◽  
Centrifugal Fans ◽  
Computational Fluid Dynamics Cfd

Abstract This work presents an analysis of the aerodynamic performance of a centrifugal fan with forward curved blades (Sirocco) applied to electric motors. In this analysis were carried out computational fluid dynamics (CFD) simulations and experimental tests for comparison of results. The focus of this analysis is the performance comparison among three different models of general connection interface that are required for the connection between the grids of the rotating and stationary domains of CFD simulation, considering the method adopted by the Ansys CFX, software used as computational tool. Thereby, Frozen Rotor, Stage, and Transient Rotor-Stator were the interface models evaluated. For comparison reference, the experimental data were used to evaluate the performance of each interface models for overall operating range of the fan.

scholarly journals Numerical investigation of flow distribution in tubular space of fin-and-tube heat exchanger

2018 ◽  
Vol 240 ◽  
pp. 02011
Author(s):  
Tomasz Stelmach
Keyword(s):  
Heat Exchanger ◽  
Numerical Investigation ◽  
Cfd Simulation ◽  
Tube Bundle ◽  
Cross Flow ◽  
Flow Distribution ◽  
Volumetric Flow Rate ◽  
Tube Heat Exchanger ◽  
Ansys Cfx ◽  
Measurement Results

This paper presents the experimental and numerical investigation of flow distribution in the tubular space of cross-flow fin-and-tube heat exchanger. The tube bundle with two rows arranged in staggered formation is considered. A standard heat exchanged manifold, with inlet nozzle pipe located asymmetrically is considered. The outlet nozzle pipe is located in the middle of the outlet manifold. A developed experimental setup allows one to measure volumetric flow rate in heat exchanger tubes using the ultrasonic flowmeters. The measurement results are then compared with CFD simulation in ANSYS CFX code using the SSG Reynolds Stress turbulence model, and a good agreement is found for tube Re numbers varied from 1800 to 3100.

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