scholarly journals The Computational fluid dynamics Performance Analysis of Horizontal Axis Wind Turbine

Author(s):  
Naji Abdullah Mezaal ◽  
Osintsev K. V. ◽  
Alyukov S.V.

<span lang="EN-US">Computational fluid dynamics (CFD) simulations were performed in the present study using ANSYS Fluent 18.0, a commercially available CFD package, to characterize the behaviour of the new HAWT. Static three-dimensional CFD simulations were conducted. The static torque characteristics of the turbine and the simplicity of design highlight its suitability for the GE 1.5xle turbine. The major factor for generating the power through the HAWT is the velocity of air and the position of the blade angle in the HAWT blade assembly. The study presents the effect of The blade is 43.2 meters long and starts with a cylindrical shape at the root and then transitions to the airfoils S818, S825 and S826 for the root, body and tip, respectively. This blade also has pitch to vary as a function of radius, giving it a twist and the pitch angle at the blade tip is 4 degrees. This blade was created to be similar in size to a GE 1.5xle turbine by Cornell University [1]. In addition, note that to represent the blade being connected to a hub, the blade root is offset from the axis of rotation by 1 meter. The hub is not included in our model. The experimental analysis of GE 1.5xle turbine, so that possible the result of CFD analysis can be compared with theoretical calculations. CFD workbench of ANSYS is used to carry out the virtue simulation and testing. The software generated test results are validated through the experimental readings. Through this obtainable result will be in the means of maximum constant power generation from HAWT.</span>

Author(s):  
Sing Ngie David Chua ◽  
Boon Kean Chan ◽  
Soh Fong Lim

Thermal accumulation in a car cabin under direct exposure to sunlight can be extremely critical due to the risk of heatstroke especially to children who are left unattended in the car. There are very limited studies in the literature to understand the thermal behaviour of a car that is parked in an open car park space and the findings are mostly inconsistent among researchers. In this paper, the studies of thermal accumulation in an enclosed vehicle by experimental and computational fluid dynamics simulation approaches were carried out. An effective and economical method to reduce the heat accumulation was proposed. Different test conditions such as fully enclosed, fully enclosed with sunshade on front windshield and different combinations of window gap sizes were experimented and presented. Eight points of measurement were recorded at different locations in the car cabin and the results were used as the boundary conditions for the three-dimensional computational fluid dynamics simulation. The computational fluid dynamics software used was ANSYS FLUENT 16.0. The results showed that the application of sunshade helped to reduce thermal accumulation at car cabin by 11.5%. The optimum combination of windows gap size was found to be with 4-cm gap on all four windows which contributed to a 21.1% reduction in car cabin temperature. The results obtained from the simulations were comparable and in agreement with the experimental tests.


2018 ◽  
Vol 42 (2) ◽  
pp. 128-135 ◽  
Author(s):  
S Horb ◽  
R Fuchs ◽  
A Immas ◽  
F Silvert ◽  
P Deglaire

NENUPHAR aims at developing the next generation of large-scale floating offshore vertical-axis wind turbine. To challenge the horizontal-axis wind turbine, the variable blade pitch control appears to be a promising solution. This article focuses on blade pitch law optimization and resulting power and thrust gain depending on the operational conditions. The aerodynamics resulting from the implementation of a variable blade pitch control are studied through numerical simulations, either with a three-dimensional vortex code or with two-dimensional Navier-stokes simulations (two-dimensional computational fluid dynamics). Results showed that the three-dimensional vortex code used as quasi-two-dimensional succeeded to give aerodynamic loads in very good agreement with two-dimensional computational fluid dynamics simulation results. The three-dimensional-vortex code was then used in three-dimensional configuration, highlighting that the variable pitch can enhance the vertical-axis wind turbine power coefficient ( Cp) by more than 15% in maximum power point tracking mode and decrease it by more than 75% in power limitation mode while keeping the thrust below its rated value.


Aviation ◽  
2020 ◽  
Vol 23 (4) ◽  
pp. 114-122
Author(s):  
Zbigniew Czyż ◽  
Paweł Karpiński

The paper presents some of the works related to the project of modern gyrocopter construction with the possibility of a short start, known as "jump-start". It also presents a methodology related to numerical calculations using Computational Fluid Dynamics based on ANSYS Fluent three-dimensional solver. The purpose of the work was to calculate the forces and aerodynamic moments acting on the gyrocopter stabilizers. The calculations were carried out for a range of angle of attack α from –20° to +25° and for a sideslip angle β from 0° to 20°. Based on the calculations carried out, analysis of the impact of the slip angle on the load on the stabilizers has been made.


Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4983 ◽  
Author(s):  
Miguel Sumait Sy ◽  
Binoe Eugenio Abuan ◽  
Louis Angelo Macapili Danao

Wind energy is one of the fastest growing renewable energy sources, and the most developed energy extraction device that harnesses this energy is the Horizontal Axis Wind Turbine (HAWT). Increasing the efficiency of HAWTs is one important topic in current research with multiple aspects to look at such as blade design and rotor array optimization. This study looked at the effect of wingtip devices, a split winglet, in particular, to reduce the drag induced by the wind vortices at the blade tip, hence increasing performance. Split winglet implementation was done using computational fluid dynamics (CFD) on the National Renewable Energy Lab (NREL) Phase VI sequence H. In total, there are four (4) blade configurations that are simulated, the base NREL Phase VI sequence H blade, an extended version of the previous blade to equalize length of the blades, the base blade with a winglet and the base blade with split winglet. Results at wind speeds of 7 m/s to 15 m/s show that adding a winglet increased the power generation, on an average, by 1.23%, whereas adding a split winglet increased it by 2.53% in comparison to the extended blade. The study also shows that the increase is achieved by reducing the drag at the blade tip and because of the fact that the winglet and split winglet generating lift themselves. This, however, comes at a cost, i.e., an increase in thrust of 0.83% and 2.05% for the blades with winglet and split winglet, respectively, in comparison to the extended blade.


2020 ◽  
Author(s):  
Yu-Jen Hou ◽  
Hung-Pin Huang

&lt;p&gt;In Taiwan, arched groundsill is frequently used as soil-and-water conservation structures for stabilizing creek bed, guiding flow direction, decreasing the slope of creek bed and reducing the scour effect. Even though much more arched grounsill was built in wild creek recently, its mechanical mechanism is still unclear.&lt;/p&gt;&lt;p&gt;In order to explore the characteristics of arched groundsill, this study intends to find out the scale of stress, moment and displacement distribution on the various curvature arched groundsills by means of the structural analysis software, ABAQUS. Simultaneously, the three-dimensional computational fluid dynamics software, ANSYS-FLUENT, is applied to show the flow condition of different setups. Preliminary result shows that the maximum stress and displacement of arched groundsill increase with curvature. The maximum moment decreases slightly firstly and increases sharply later with curvature.&lt;/p&gt;


2018 ◽  
Vol 18 (5) ◽  
pp. 1518-1530 ◽  
Author(s):  
Jie Zhang ◽  
Tien Yee

Abstract Flow near pump intakes is three-dimensional in nature, and is affected by many factors such as the geometry of the intake bay, uniformity of approach flow, critical submergence, placements and operation combinations of pumps and so on. In the last three decades, advancement of numerical techniques coupled with the increase in computational resources made it possible to conduct computational fluid dynamics (CFD) simulations on pump intakes. This article reviews different aspects involved in CFD modeling of pump station intakes, outlines the challenges faced by current CFD modelers, and provides an attempt to forecast future direction of CFD modeling of pump intakes.


2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Ashkan Rasouli ◽  
Horia Hangan

Wind mapping is of utmost importance in various wind energy and wind engineering applications. The available wind atlases usually provide wind data with low spatial resolution relative to the wind turbine height and usually neglect the effect of topographic features with relatively large or sudden changes in elevation. Two benchmark cases are studied for computational fluid dynamics (CFD) model evaluation on smooth two-dimensional (2D) and three-dimensional (3D) hills. Thereafter, a procedure is introduced to build CFD model of a complex terrain with high terrain roughness heights (dense urban area with skyscrapers) starting from existing topography maps in order to properly extend the wind atlas data over complex terrains. CFD simulations are carried out on a 1:3000 scale model of complex topographic area using Reynolds averaged Navier–Stokes (RANS) equations along with shear stress transport (SST) k-ω turbulence model and the results are compared with the wind tunnel measurements on the same model. The study shows that CFD simulations can be successfully used in qualifying and quantifying the flow over complex topography consisting of a wide range of roughness heights, enabling to map the flow structure with very high spatial resolution.


2016 ◽  
Vol 3 (7) ◽  
pp. 160298 ◽  
Author(s):  
Jin Suo ◽  
Erin E. Edwards ◽  
Ananyaveena Anilkumar ◽  
Todd Sulchek ◽  
Don P. Giddens ◽  
...  

To delineate the influence of hemodynamic force on cell adhesion processes, model in vitro fluidic assays that mimic physiological conditions are commonly employed. Herein, we offer a framework for solution of the three-dimensional Navier–Stokes equations using computational fluid dynamics (CFD) to estimate the forces resulting from fluid flow near a plane acting on a sphere that is either stationary or in free flow, and we compare these results to a widely used theoretical model that assumes Stokes flow with a constant shear rate. We find that while the full three-dimensional solutions using a parabolic velocity profile in CFD simulations yield similar translational velocities to those predicted by the theoretical method, the CFD approach results in approximately 50% larger rotational velocities over the wall shear stress range of 0.1–5.0 dynes cm −2 . This leads to an approximately 25% difference in force and torque calculations between the two methods. When compared with experimental measurements of translational and rotational velocities of microspheres or cells perfused in microfluidic channels, the CFD simulations yield significantly less error. We propose that CFD modelling can provide better estimations of hemodynamic force levels acting on perfused microspheres and cells in flow fields through microfluidic devices used for cell adhesion dynamics analysis.


2021 ◽  
Vol 4 (1) ◽  
pp. 22-32
Author(s):  
Joseph Ebelait ◽  
Semwogerere Twaibu ◽  
Moses Nagulama ◽  
Asaph Muhumuza Keikara

This study describes the linkage leakage in sewage pipes through a porous media using computational fluid dynamics with the presence of one leak through fluid simulations using the Ansys fluent 17.2 commercial software based on standard k-ε model under steady-state condition. The pipe section is three-dimensional with a pipe length of 40 mm, a pipe diameter of 20 mm, and leak orifice diameter of 2 mm with a porous media of length 25 mm and width 30 mm. The interest of this study was to reduce the rate of sewage leakage in pipes laid underground by use computational fluid dynamics. The simulation results obtained shows that when the flow is subjected to an outlet pressure between 100000 Pa to 275000 Pa the sewage leaks at pressures of 99499 Pa to 278799.8 Pa indicating that increase of outlet pressures increases the pressure at the leak point and also an increase in the inlet velocity resulted into an increase of velocity at the leak point and no significant change in sewage flow rate with increased inlet velocities. Therefore, monitoring of the pressure and velocity fields along the pipeline is an extremely important tool to identify leaks since these fields are affected by perturbations both before the leak point and after the leak point.


Author(s):  
A D Augst ◽  
D C Barratt ◽  
A D Hughes ◽  
S A McG Thom ◽  
X Y Xu

Computational fluid dynamics (CFD) flow simulation techniques have the potential to enhance understanding of how haemodynamic factors are involved in atherosclerosis. Recently, three-dimensional ultrasound has emerged as an alternative to other three-dimensional imaging techniques, such as magnetic resonance angiography (MRA). The method can be used to generate accurate vascular geometry suitable for CFD simulations and can be coupled with Doppler ultrasound to provide physiologically realistic flow boundary conditions. However, there are various ways to utilize the flow data acquired, possibly leading to different results regarding both flow and wall shear stress patterns. A disadvantage of three-dimensional ultrasound for imaging the carotid bifurcation has been established as being the scanning limitation of the jawbone position. This may make artificial extensions of the internal and/or external carotid arteries necessary, which in turn may influence the predicted flow patterns. Flow simulations were carried out for three outflow calculation schemes as well as four geometries with different extensions to the carotid daughter vessels. It was found that variation of flow patterns was more strongly influenced by the outflow conditions than by the extensions of the daughter vessels. Consequently, it is recommended that for future CFD simulations of carotid flow using three-dimensional ultrasound data, the outflow boundary conditions should rely on the most accurate measurement available, and flow data recorded in the common and internal carotid are considered more reliable than data from the external carotid. Even though the extended lengths of the daughter vessels have insignificant effects on the predicted haemodynamic parameters, it would be a safer option to extend the internal carotid by approximately three times the diameter of the common carotid artery.


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