CFD analysis of a straight bladed vertical axis wind turbine with selected transition and turbulence models /
At present, interests for developing wind turbines are rising due to the high demand in green energies production. The advantages of Straight-bladed Vertical Axis Wind Tur- bine (SB-VAWT) over any usual Horizontal Axis Wind Turbine (HAWT), is mainly due to its simple blade design and its insensitivi...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
Kuala Lumpur :
Kulliyyah of Engineering, International Islamic University Malaysia,
2018
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| Subjects: | |
| Online Access: | http://studentrepo.iium.edu.my/handle/123456789/4395 |
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| Summary: | At present, interests for developing wind turbines are rising due to the high demand in green energies production. The advantages of Straight-bladed Vertical Axis Wind Tur- bine (SB-VAWT) over any usual Horizontal Axis Wind Turbine (HAWT), is mainly due to its simple blade design and its insensitivity to incoming wind directions. SB-VAWT have shown to be potentionally suited the urban area due to its small built and easy to manufacture blades, along with helping in reducing air pollution concentration from ur- banization. As SB-VAWT were developed specifically for city area, a low wind speed environment is expected. Many researchers resort in carrying out performance analysis using the Computational Fluid Dynamic (CFD) analysis as a means to investigate the working of SB-VAWT in such circumstances. The purpose of this thesis is to perform CFD analysis on a small-scaled SB-VAWT using two classes of transition turbulence model namely, the Local Correlation-based Transition Model (LCTM) and the Laminar Kinetic Energy (LKE) transitional model. The CFD analysis has been performed using the Unsteady Reynolds Averaged Navier-Stokes (URANS) simulation in foam-extend software which is a fork of OpenFOAM in order to take into account the unsteady ef- fects of transitional region. Then, a time-consuming and high computational demand, three-dimensional analysis is carried out using the performing transitional turbulence model alongside with the commonly used, k- ω SST model. Despite the limited com- putational resources experienced, various ways to tackle the problem is considered. In 3D analyses, a scaled-down SB-VAWT model is used in order to reduce simulation time and avoiding the need to generate enormous number of cells. Power coefficient, CP re- sulting from the simulations are then validated against the experimental study done by researchers in a wind tunnel. It is concluded in this thesis that the application of tran- sitional turbulence model show a more conforming result with the experimental data regardless of 2D and 3D CFD analysis. Especially the LCTM, γ-Reθ, SST model shows a stable application that can be seen from the blade torque reading throughout the revolutions. Vortices visualization in 2D also show that, strong ripples at the down- stream domain is avoided when applying the LCTM. |
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| Physical Description: | xv, 105 leaves : colour illustrations ; 30cm. |
| Bibliography: | Includes bibliographical references (leaves 65-73). |