scholarly journals CFD Simulation Of Air-Flow Over A „Quarter-Circular” Object Valided By Experimental Measurement

2015 ◽  
Vol 15 (2) ◽  
Author(s):  
Juraj Králik ◽  
Oľga Hubová ◽  
Lenka Konečná
Keyword(s):  
Turbulence Model ◽  
Experimental Measurement ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Air Flow ◽  
Turbulence Models ◽  
Ansys Fluent ◽  
Circular Object ◽  
University Of Technology ◽  
Polyhedral Mesh

Abstract A Computer-Fluid-Dynamic (CFD) simulation of air-flow around quarter-circular object using commercial software ANSYS Fluent was used to study iteration of building to air-flow. Several, well know transient turbulence models were used and results were compared to experimental measurement of this object in Boundary Layer Wind Tunnel (BLWT) of Slovak University of Technology (SUT) in Bratislava. Main focus of this article is to compare pressure values from CFD in three different elevations, which were obtained from experimental measurement. Polyhedral mesh type was used in the simulation. Best results on the windward face elevations were obtained using LES turbulence model, where the averaged difference was around 7.71 %. On the leeward face elevations it was SAS turbulence model and averaged differences from was 15.91 %. On the circular face it was SAS turbulence model and averaged differences from all elevations was 12.93 %.

3-D CFD Simulation of the Airflow over a Gable Roof with Different Elevations

2015 ◽  
Vol 769 ◽  
pp. 229-234
Author(s):  
Juraj Jr. Kralik
Keyword(s):  
Wind Tunnel ◽  
Turbulence Model ◽  
Cfd Simulation ◽  
Wind Tunnel Test ◽  
Turbulence Models ◽  
Accurate Method ◽  
Navier Stokes ◽  
Ansys Fluent ◽  
Pressure Coefficients ◽  
Gable Roof

The pressure coefficients on duo-pitched roofs of separated buildings are well described by several standards. Nowadays, there are various commercial or non-commercial programs which can predict the pressure coefficients. However, the most accurate method is to perform a wind tunnel test. The aim of this paper is to simulate the airflow over a gable roof with different elevations under ANSYS Fluent 14.0 program. Examined elevations of the gable roof are 5°, 15° and 30°. Classical two equation k-ε turbulence models based on Reynolds Averaged Navier-Stokes (RANS) equations simulation were performed. Performance of each turbulence model with the increasing angel of the roof was compared.

Geometric Modeling of a Propeller Turbine Runner Using ANSYS BladeGen, Meshing Using ANSYS TurboGrid and Fluid Dynamic Simulation Using ANSYS Fluent

2016 ◽  
Vol 842 ◽  
pp. 164-177 ◽  
Author(s):  
Indra Djodikusumo ◽  
I. Nengah Diasta ◽  
Iwan Sanjaya Awaluddin
Keyword(s):  
Geometric Modeling ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Thickness Distribution ◽  
Ansys Fluent ◽  
Implementation Phase ◽  
Runner Blade ◽  
Modeling Process ◽  
Turbine Runner ◽  
Preparation Phase

This paper aims to demonstrate how to model, mesh and simulate a hydraulic propeller turbine runner based on the geometrical specification of the runner blade. Modeling process is divided into preparation and implementation phase. Preparation phase illustrates how to develop stream surfaces and passages, how to create and transform meanline and how to create an rtzt file. The profile in rtzt file has a certain fix thickness which has to be altered later. Implementation phase describes operations necessary in creating a propeller runner model in ANSYS BladeGen which consist of importing rtzt file, modifying the trailing edge properties and altering profile thickness distribution to that of 4 digits NACA airfoil standard. Grid is generated in ANSYS TurboGrid utilizing ATM Optimized topology. CFD simulation is done using the ANSYS Fluent with pressure inlet and pressure outlet boundary conditions and k-ε turbulence model. Hydraulic efficiency of the runner is calculated utilizing Turbo Topology module in ANSYS Fluent. The authors will share the advantages that may be obtained by using ANSYS BladeGen compared with the use of general CAD Systems.

scholarly journals Calculated research of aeroelastic stability of a bridge over the river Ob in Salekhard at the stage of assembling and operation

2019 ◽  
Vol 6 (3) ◽  
Author(s):  
Anastasiya Shustikova ◽  
Andrei Kozichev ◽  
Sergei Paryshev ◽  
Konstantin Strelkov
Keyword(s):  
Cfd Simulation ◽  
Load Capacity ◽  
Air Flow ◽  
Lift Coefficient ◽  
High Strength ◽  
Railway Bridge ◽  
Aeroelastic Stability ◽  
Ansys Fluent ◽  
Long Span ◽  
Long Span Bridge

Recently, long span bridge construction has been demanded for development of the regions of the Russian Federation. In terms of economy, it’s useful to build a combined road-railway bridge. Such bridges, generally, constitute a metal cross-cutting girder with carriageways on lower, upper or both zones of the girder. The major advantages of combined bridges are high strength and load capacity, plus cross-cutting to wind load. Focus of this research is a combined road-railway bridge over the Ob river at the stage of assembling and operation. The purpose of the study was to determine the limits of aeroelastic stability of combined road-railway bridge at the stage of assembling and operation using numerical simulation. To better understand the bridges behaviour in air flow, flow around a section model has been researched with CFD simulation in the ANSYS FLUENT. Then based on the given results of the calculations the dependence of the bridge vibrations on wind speed within a specified range is obtained, and also values of drag coefficient Сх, lift coefficient Су and torque coefficient Мz are received. These studies were carried out in the range of angles of attack α = ±3°. The possibility of divergence and galloping was also estimated. The results of the study made it possible to estimate the influence of air flow on combined bridge cross-cutting girder. Overall, the conducted research seems promising for further investigation and development in the field of bridge aeroelasticity.

CFD Simulation of a Supersonic Steam Ejector for Refrigeration Application

2016 ◽  
Author(s):  
Liju Su ◽  
Ramesh K. Agarwal
Keyword(s):  
Flow Field ◽  
Cfd Simulation ◽  
Fluid Pressure ◽  
Turbulence Models ◽  
Industrial Applications ◽  
Operating Conditions ◽  
Working Fluid ◽  
Entrainment Ratio ◽  
Ansys Fluent ◽  
Entrainment Velocity

Supersonic steam ejectors are widely used in many industrial applications, for example for refrigeration and desalination. The experimental evaluation of the flow field inside the ejector is relatively difficult and costly due to the occurrence of shock after the velocity of the steam reaches over the sonic level in the ejector. In this paper, numerical simulations are conducted to investigate the detailed flow field inside a supersonic steam (water vapor being the working fluid) ejector. The commercial computational fluid dynamics (CFD) flow solver ANSYS-Fluent and the mesh generation software ANSYS-ICEM are used to predict the steam performance during the mixing inside the ejector by employing two turbulence models, the k-ω SST and the k-ε realizable models. The computed results are validated against the experimental data. The effects of operating conditions on the efficiency of the ejector such as the primary fluid pressure and condenser pressure are studied to obtain a better understanding of the mixing process and entrainment. Velocity contours, pressure plots and shock region analyses provide a good understanding for optimization of the ejector performance, in particular how to increase the entrainment ratio.

Capability of Two Equation k-ω Turbulence Model to Predict Pressure Values on “Quarter-Circular” Object

2016 ◽  
Vol 837 ◽  
pp. 209-213
Author(s):  
Juraj Kralik ◽  
Olga Hubova ◽  
Lenka Konecna
Keyword(s):  
Reynolds Number ◽  
Turbulent Flows ◽  
Turbulence Model ◽  
Fluid Dynamic ◽  
Convergence Time ◽  
Large Reynolds Number ◽  
Mean Values ◽  
Circular Object ◽  
Basic Characteristics ◽  
Property Changes

Turbulence is a flow regime characterized by chaotic property changes. Randomness, fluctuations, vorticity and large Reynolds number (Re) are the basic characteristics of turbulent flows. In this contribution is Computer Fluid Dynamic simulation of air-flow over an obstacle in shape of “quarter-circular” object compared to the data from previous work. This comparison is focused on mean values of pressure in 16 selected points at different elevations. k-ω turbulence model performed well (convergence, time, CPU) and the overall error is 13.61 %.

scholarly journals Earth Air Tunnel Heat Exchanger for Building Cooling and Heating

2021 ◽  
Author(s):  
Nasim Hasan ◽  
Mohd Arif ◽  
Mohaideen Abdul Khader
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Numerical Algorithms ◽  
Ansys Fluent ◽  
Helical Pipe ◽  
Complex Fluid ◽  
Set Up ◽  
Building Cooling

The computational fluid dynamic (CFD) is an influential method for measuring Heat transfer profiles for typical meteorological years. CFD codes are managed by numerical algorithms that may undertake fluid glide headaches. CFD offers the numerical results of partial differential equations with main airflow and heat transfer in a discretized association. The complex fluid glide and the warmth transfer publications worried in any heat exchanger can be determined with the help of the CFD software program (Ansys Fluent). A study states and framework which implicitly rely on the computational fluid dynamics, which is being formulated for computing the efficiency-related parameters of the thermal part and the capability of the EATHE system for cooling. A CFD simulation program is being used for modeling the system. The framework is being validated with the help of the simulation set-up. A thermal model was developed to analyze thermal energy accumulated in soil/ground for the purpose of room cooling/heating of buildings in the desert (hot and dry) climate of the Bikaner region. In this study, the optimization of EATHE design has been performed for finding the thermal performance of straight, spiral, and helical pipe earth air tunnel heat exchanger and Heat transfer rate for helical pipe was found maximum among all designs.

scholarly journals Numerical Simulation of the Performance Characteristics of the Hybrid Closed Circuit Cooling Tower

2008 ◽  
Vol 13 (1) ◽  
pp. 89-101 ◽  
Author(s):  
M. M. A. Sarker ◽  
E. Kim ◽  
G. C. Moon ◽  
J. I. Yoon
Keyword(s):  
Pressure Drop ◽  
Experimental Measurement ◽  
Cooling Tower ◽  
Cfd Simulation ◽  
Air Flow ◽  
Flow Distribution ◽  
Cooling Capacity ◽  
Performance Characteristics ◽  
Closed Circuit ◽  
Flow Rates

The performance characteristics of the Hybrid Closed Circuit Cooling Tower (HCCCT) have been investigated applying computational fluid dynamics (CFD). Widely reported CFD techniques are applied to simulate the air-water two phase flow inside the HCCCT. The pressure drop and the cooling capacity were investigated from several perspectives. Three different transverse pitches were tested and found that a pitch of 45 mm had lower pressure drop. The CFD simulation indicated that when air is supplied from the side wall of the HCCCT, the pressure drop can be over predicted and the cooling capacity can be under predicted mainly due to the non-uniform air flow distribution across the coil bank. The cooling capacity in wet mode have been calculated with respect to wet-bulb temperature (WBT) and cooling water to air mass flow rates for different spray water volume flow rates and the results were compared to the experimental measurement and found to conform well for the air supply from the bottom end. The differences of the cooling capacity and pressure drop in between the CFD simulation and experimental measurement in hybrid mode were less than 5 % and 7 % respectively for the uniform air flow distribution.

scholarly journals Application of different turbulence models for improving construction of small-scale boiler fired by solid fuel

2017 ◽  
Vol 21 (suppl. 3) ◽  
pp. 809-823
Author(s):  
Nebojsa Manic ◽  
Vladimir Jovanovic ◽  
Dragoslava Stojiljkovic ◽  
Zagorka Brat
Keyword(s):  
Turbulence Model ◽  
Solid Fuel ◽  
Turbulence Modeling ◽  
Turbulence Models ◽  
Experimental Tests ◽  
Computer Hardware ◽  
Small Scale ◽  
Heat Output ◽  
Ansys Fluent ◽  
Model Fluid

Due to the rapid progress in computer hardware and software, CFD became a powerful and effective tool for implementation turbulence modeling in defined combustion mathematical models in the complex boiler geometries. In this paper the commercial CFD package, ANSYS FLUENT was used to model fluid flow through the boiler, in order to define velocity field and predict pressure drop. Mathematical modeling was carried out with application of Standard, RNG, and Realizable k-? turbulence model using the constants presented in literature. Three boilers geometry were examined with application of three different turbulence models with variants, which means consideration of 7 turbulence model arrangements in FLUENT. The obtained model results are presented and compared with data collected from experimental tests. All experimental tests were performed according to procedures defined in the standard SRPS EN 303-5 and obtained results are presented in this paper for all three examined geometries. This approach was used for improving construction of boiler fired by solid fuel with heat output up to 35 kW and for selection of the most convenient construction.

CFD Simulation of 5×5 Rod Bundles With Split-Type Spacers

2013 ◽  
Author(s):  
K. Podila ◽  
J. Bailey ◽  
Y. F. Rao ◽  
M. Krause
Keyword(s):  
Cfd Simulation ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Atomic Energy ◽  
Rod Bundles ◽  
Spacer Grid ◽  
Two Phase ◽  
Ansys Fluent ◽  
Computational Fluid Dynamics Cfd ◽  
Canada Limited

Atomic Energy of Canada Limited (AECL) has initiated a program to develop Computational Fluid Dynamics (CFD) capability for simulating single- and two-phase flows in rod-bundles. In the current work, a 5×5 rod assembly with a split-type spacer grid is simulated with ANSYS Fluent 14 using unsteady simulations with a fully conformal hybrid mesh (wall y+∼30). This work represents results of AECL’s recent participation in the OECD/NEA organized CFD benchmarking exercise on the MATiS-H experiment performed at the Korean Atomic Energy Research Institute (KAERI). The sensitivity to turbulence models is tested using the standard k-ε and the Reynolds stress model (RSM). Reasonable agreement is achieved between the calculated and experimental velocity values in the region close to the spacer grid, whereas turbulence intensity values are underpredicted compared to the experiments.

Numerical Prediction of a Multistage Centrifugal Pump Performance With Stationary and Moving Mesh

2015 ◽  
Author(s):  
Alessandro Nocente ◽  
Tufan Arslan ◽  
Torbjørn K. Nielsen
Keyword(s):  
Centrifugal Pump ◽  
Turbulence Model ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Transient State ◽  
Computational Effort ◽  
Phase Flow ◽  
Two Phase ◽  
Ansys Fluent ◽  
Performance Report

The present work reviews a comparison between calculations of a steady and unsteady three dimensional (3D) flow past the diffuser channels of a centrifugal pump. The commercial software ANSYS Fluent has been used. The considered domain is one of the three stages, since each has exactly the same design. In the first part, simulations are carried out at the best efficiency point (BEP) both steady and transient state, single phase flow and four different turbulence models. Results are compared with the performance report from the manufacturer. In the second part, only the realizable k-ε turbulence model has been taken into account. The simulations have been repeated for different mass flows and the results were again compared with the data from the manufacturer. The comparison performed in the first part shows that integral quantities results are not sensibly influenced by the turbulence model. The comparison at different mass flow shows that the steady state simulations demonstrated to be a good approximation of the transient state, always containing the error within an acceptable limit. The minor computational effort needed makes it attractive to be used for further investigations which will involve two-phase flow studies on the same pump.

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