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dc.contributor.author
Dimitriadis, Emmanouil
en
dc.date.accessioned
2015-06-18T12:37:51Z
dc.date.available
2015-09-27T05:56:45Z
dc.date.issued
2015-06-18
dc.identifier.uri
https://repository.ihu.edu.gr//xmlui/handle/11544/430
dc.rights
Default License
dc.title
Flow Field Investigation of
a Horizontal Axis Wind
Turbine
en
heal.type
masterThesis
heal.keyword
Turbines--Aerodynamics
en
heal.keyword
Dissertations, Academic
en
heal.language
en
heal.access
free
el
heal.license
http://creativecommons.org/licenses/by-nc/4.0
heal.recordProvider
School of Science and Technology, MSc in Energy Systems
heal.publicationDate
2012-10
heal.bibliographicCitation
Dimitriadis, Emmanouil, 2012, Flow field investigation of a horizontal axis wind turbine ,Master's Dissertation, International Hellenic University
en
heal.abstract
The MSc thesis concerns the study of the aerodynamics of a horizontal axis wind
turbine.
Nowadays the design of wind turbines is based on design codes that originate from
the Blade Element Momentum Theory (BEMT). This design tools use also
correction models which are trying to correct the shortcomings of the above
theory. The significant increase of the size of wind turbines stimulates the
importance of accurate design.
Aim of this study is to model and investigate the physical characteristics of the
flow field around a wind turbine. In order to achieve that Computational Fluid
Dynamics (CFD) design tools are used.
First, a two-dimensional approach was executed using CFD-Reynolds Average
Navier-Stokes (CFD-RANS) calculations for NACA4415 airfoil in order to validate
the capability of the selected turbulence models, k-ω SST and RSM. The results
were compared with experimental data taken from literature as well as with those
produced by the airfoil design and analysis tool XFOIL. All CFD calculations were
executed using the commercial package ANSYS CFX. Following the twodimensional
approach, a design of a blade based on BEMT was performed. The
airfoil NACA4415 that was examined in the two-dimensional approach was used
for the design of the blade and the open source turbine calculation tool QBLADE
was selected for this purpose.
The three-dimensional approach in CFD was carried out using a moving reference
frame. The calculations were performed for six degrees angle of attack, since for
this angle the selected airfoil displayed the highest lift to drag ratio. The rotational
effects on the blade were studied using four cross sections along the blade and
studying the pressure and velocity distribution. The k-ω SST turbulence model
vi
presented the better performance. Finally the performance of the wind turbine
was investigated and a comparison with the results of the BEMT design and
analysis tool was made.
en
heal.tableOfContents
ABSTRACT ................................................................................................................... V
ACKNOWLEDGEMENTS ........................................................................................ VII
CONTENTS ................................................................................................................. IX
1. INTRODUCTION ..................................................................................................... 1
2. LITERATURE REVIEW .......................................................................................... 5
2.1. ENERGY DEMAND AND WIND POWER ................................................................. 5
2.2. WIND TURBINE BLADE DESIGN PARAMETERS .................................................... 6
2.3. BASIC DEFINITIONS .......................................................................................... 10
2.4. WIND TURBINE PERFORMANCE ........................................................................ 11
2.4.1. Cp-λ performance curve ................................................................... 12
2.4.2. CQ-λ performance curve .................................................................. 13
2.4.3. CT-λ performance curve ................................................................... 14
2.5. A BRIEF REVIEW OF AERODYNAMIC MODELS ................................................... 14
2.5.1. Actuator disc method ........................................................................ 14
2.5.2. Lifting line, panel and vortex methods ........................................... 16
2.5.3. Blade element momentum method ................................................ 19
2.6. BOUNDARY LAYER THEORY ............................................................................. 23
2.6.1. Laminar and turbulent layer ............................................................ 23
2.6.2. Boundary layer thickness ................................................................ 24
2.6.3. Transition ............................................................................................ 25
2.6.4. External pressure gradient .............................................................. 25
2.6.5. Boundary layer separation .............................................................. 26
2.7. EFFECTS OF ROTATION ON FLOW .................................................................... 27
2.8. NAVIER-STOKES SOLVERS AND WIND TURBINES ............................................ 30
3. TWO-DIMENSIONAL CFD COMPUTATIONS ................................................. 33
3.1. THE SOFTWARE CFX ....................................................................................... 33
x
3.2. TURBULENCE MODELS .....................................................................................34
3.3. COMPUTATIONAL GRID AND DOMAIN ................................................................37
3.4. CFD RESULTS AND VALIDATION .......................................................................40
4. THREE DIMENSIONAL MODELING .................................................................59
4.1. BLADE ELEMENT MOMENTUM THEORY ...........................................................59
4.2. BLADE DESIGN ..................................................................................................61
5. THREE DIMENSIONAL CFD COMPUTATIONS .............................................65
5.1. ROTATING REFERENCE FRAME MODELING ......................................................65
5.2. COMPUTATIONAL GRID AND DOMAIN ................................................................65
5.3. CFD CALCULATIONS AND EVALUATION ............................................................69
CONCLUSIONS ...........................................................................................................79
BIBLIOGRAPHY ..........................................................................................................81
APPENDIX A ................................................................................................................85
APPENDIX B ..............................................................................................................101
en
heal.advisorName
Ass. Prof. Bassileiades
en
heal.committeeMemberName
Ass. Prof. Bassileiades
en
heal.committeeMemberName
Dr. Sardi
en
heal.committeeMemberName
Dr. Martinopoulos
en
heal.academicPublisher
School of Science &Technology, Master of Science (MSc) in Energy Systems
en
heal.academicPublisherID
ihu
heal.numberOfPages
128
heal.fullTextAvailability
true
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