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Impact of Icing on Wind Turbines Aerodynamic
Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.ORCID-id: 0000-0002-6025-2280
2018 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)Alternativ tittel
Påverkan av isbildning på vindkraftverk aerodynamik (svensk)
Abstract [en]

Wind energy covered 11.6% of Europe electricity demand in 2017. Region with cold climates represent a strong potential for wind energy companies because of their sparse population and proper wind conditions. The global wind energy installations in cold climate regions is forecasted to reach a capacity of 186 GW by the end of 2020. But wind turbines installed in cold climate regions are prone to the risks of ice accumulation which affects their aerodynamics behavior, as well as the safety, and structural loads.

The aerodynamic forces on wind turbine can be affected in two main ways: ice accretion changes the blade profile, and thus the flow path curvature, and the surface roughness. The importance of these two parameters depend on the ice type. The target ice type for this thesis is the smooth leading-edge glaze ice with horn shape. The aerodynamic consequences of the blade profile change because of the mentioned ice type are studied in detail. 

The findings of this thesis are classified in five main sections. The first section considers the methodology to model the performance of a wind turbine. The wake behind the turbine is also explored. Different aspects of the simulation methods with computational fluid dynamics using the Reynolds-averaged Navier-Stokes equations are investigated in both steady state and transient. In the second section, the time-dependent effects of icing are studied, exploring the moving vortices created by the irregularity of the ice and their frequencies and amplitudes. The main frequency modes of the flow dynamics were analyzed. In the third section, three-dimensional simulation of icing is implemented and the fluid flow arrangement through the rotor is investigated. Two well-recognized approaches are applied and compared, which are Blade Element Momentum (BEM) and CFD. An automated setup is programmed and launched to implement multiple CFD simulations to provide the aerodynamic data for structural analysis in the fourth section. The developed methodology is illustrated on a large-scale wind turbine. In section five, the effects of the uncertain level of ice-accretion is studied through an uncertainty quantification method. The aerodynamic losses are statistically discussed. Then, a scenario study is conducted according to the obtained polynomial chaos expansion, in which the probability distribution of wind power loss due to icing is inspected.

The achievements of this thesis can be used in to design of a wind turbine which is supposed to work in a cold climate, as well as assess the economics of a predesigned wind turbine working in a cold region.

sted, utgiver, år, opplag, sider
Luleå: Luleå tekniska universitet, 2018.
Serie
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
URN: urn:nbn:se:ltu:diva-71186ISBN: 978-91-7790-228-7 (tryckt)ISBN: 978-91-7790-229-4 (digital)OAI: oai:DiVA.org:ltu-71186DiVA, id: diva2:1255459
Disputas
2018-12-06, E231, Luleå, Luleå, 13:00 (engelsk)
Opponent
Veileder
Tilgjengelig fra: 2018-10-15 Laget: 2018-10-12 Sist oppdatert: 2020-01-07bibliografisk kontrollert
Delarbeid
1. Investigation of the numerical methodology of a model wind turbine simulation
Åpne denne publikasjonen i ny fane eller vindu >>Investigation of the numerical methodology of a model wind turbine simulation
2018 (engelsk)Inngår i: Journal of Applied Fluid Mechanics, ISSN 1735-3572, E-ISSN 1735-3645, Vol. 11, nr 3, s. 527-544Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The present work aims to investigate different methodologies for the numerical simulation of an upwind three-bladed wind turbine; which is supposed to be a base model to simulate icing in cold climate windmills. That is a model wind turbine for which wind tunnel tests have been completed at the Norwegian University of Science and Technology (NTNU). Using the assumption of axisymmetry, one-third of rotor has been modeled and periodic boundaries applied to include the effects of other blades. Then the full rotor was studied with transient simulation. To take in the effects of wind turbine wakes, the wind tunnel entrance and exit have been considered 4 and 5 diameters upstream and downstream of the rotor plane, respectively. Furthermore, the effects of tower and nacelle are included in a full-scale transient model of the wind tunnel. Structured hexa mesh has been created and the mesh is refined up to y+=1 in order to resolve the boundary layer. The simulations were performed using standard k-e, Shear Stress Transport (SST) model and a sophisticated model Scale-Adaptive Simulation (SAS)-SST to investigate the capability of turbulence models at design and off-design conditions The performance parameters, i.e., the loads coefficients and the wake behind the rotor were selected to analyze the flow over the wind turbine. The study was conducted at both design and offdesign speeds. The near wake profiles resulted from the transient simulation match well with the experiments at all the speed ranges. For the wake development modelling at high TSR, the present simulation needs to be improved, while at low and moderate TSR the results match with the experiments at far wake too. The agreement between the measurements and CFD is better for the power coefficient than for the thrust coefficient

sted, utgiver, år, opplag, sider
Isfahan University of Technology, 2018
HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-68860 (URN)10.18869/acadpub.jafm.73.246.28028 (DOI)000436179000001 ()2-s2.0-85046788836 (Scopus ID)
Merknad

Validerad;2018;Nivå 2;2018-05-23 (andbra)

Tilgjengelig fra: 2018-05-23 Laget: 2018-05-23 Sist oppdatert: 2018-10-15bibliografisk kontrollert
2. Numerical Study of Aerodynamic Characteristics of a Symmetric NACA Section with Simulated Ice Shapes
Åpne denne publikasjonen i ny fane eller vindu >>Numerical Study of Aerodynamic Characteristics of a Symmetric NACA Section with Simulated Ice Shapes
2016 (engelsk)Inngår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 753 A, artikkel-id 022055Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

To develop a numerical model of icing on wind turbine blades, a CFD simulation was conducted to investigate the effect of critical ice accretions on the aerodynamic characteristics of a 0.610 m chord NACA 0011 airfoil section. Aerodynamic performance coefficients and pressure profile were calculated and compared with the available measurements for a chord Reynolds number of 1.83x106. Ice shapes were simulated with flat plates (spoiler-ice) extending along the span of the wing. Lift, drag, and pressure coefficients were calculated in zero angle of attack through the steady state and transient simulations. Different approaches of numerical studies have been applied to investigate the icing conditions on the blades. The simulated separated flow over the sharp spoilers is challenging and can be seen as a worst test case for validation. It allows determining a reliable strategy to simulate real ice shapes [1] for which the detailed validation cannot easily be provided.

HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-59497 (URN)10.1088/1742-6596/753/2/022055 (DOI)2-s2.0-84995538957 (Scopus ID)
Konferanse
6th International Conference “The Science of Making Torque from Wind” (TORQUE 2016, 5-7 October, 2016 at Technische Universität München
Merknad

2016-10-10 (andbra);Konferensartikel i tidskrift

Tilgjengelig fra: 2016-10-10 Laget: 2016-10-05 Sist oppdatert: 2018-10-15bibliografisk kontrollert
3. Time-Dependent Effects of Glaze Ice on the Aerodynamic Characteristics of an Airfoil
Åpne denne publikasjonen i ny fane eller vindu >>Time-Dependent Effects of Glaze Ice on the Aerodynamic Characteristics of an Airfoil
2018 (engelsk)Inngår i: International Journal of Rotating Machinery, ISSN 1023-621X, E-ISSN 1542-3034, Vol. 2018, artikkel-id 2981739Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The main objective of this study is to estimate the dynamic loads acting over a glaze-iced airfoil. This work studies the performance of unsteady Reynolds-averaged Navier-Stokes (URANS) simulations in predicting the oscillations over an iced airfoil. The structure and size of time-averaged vortices are compared to measurements. Furthermore, the accuracy of a two-equation eddy viscosity turbulence model, the shear stress transport (SST) model, is investigated in the case of the dynamic load analysis over a glaze-iced airfoil. The computational fluid dynamic analysis was conducted to investigate the effect of critical ice accretions on a 0.610 m chord NACA 0011 airfoil. Leading edge glaze ice accretion was simulated with flat plates (spoiler-ice) extending along the span of the blade. Aerodynamic performance coefficients and pressure profiles were calculated and validated for the Reynolds number of 1.83 × 106. Furthermore, turbulent separation bubbles were studied. The numerical results confirm both time-dependent phenomena observed in previous similar measurements: (1) low-frequency mode, with a Strouhal number Sth≈0,013–0.02, and (2) higher frequency mode with a Strouhal number StL≈0,059–0.69. The higher frequency motion has the same characteristics as the shedding mode and the lower frequency motion has the flapping mode characteristics

sted, utgiver, år, opplag, sider
Hindawi Publishing Corporation, 2018
HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-67947 (URN)10.1155/2018/2981739 (DOI)2-s2.0-85046259848 (Scopus ID)
Merknad

Validerad;2018;Nivå 1;2018-03-15 (andbra)

Tilgjengelig fra: 2018-03-15 Laget: 2018-03-15 Sist oppdatert: 2018-10-15bibliografisk kontrollert
4. Numerical Investigation of the Aeroelastic Behavior of a Wind Turbine with Iced Blades
Åpne denne publikasjonen i ny fane eller vindu >>Numerical Investigation of the Aeroelastic Behavior of a Wind Turbine with Iced Blades
2019 (engelsk)Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, nr 12, artikkel-id 2422Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Wind turbines installed in cold-climate regions are prone to the risks of ice accumulation which affects their aeroelastic behavior. The studies carried out on this topic so far considered icing in a few sections of the blade, mostly located in the outer part of the blade, and their influence on the loads and power production of the turbine are only analyzed. The knowledge about the influence of icing in different locations of the blade and asymmetrical icing of the blades on loads, power, and vibration behavior of the turbine is still not matured. To improve this knowledge, multiple simulation cases are needed to run with different ice accumulations on the blade considering structural and aerodynamic property changes due to ice. Such simulations can be easily run by automating the ice shape creation on aerofoil sections and two-dimensional (2-D) Computational Fluid Dynamics (CFD) analysis of those sections. The current work proposes such methodology and it is illustrated on the National Renewable Energy Laboratory (NREL) 5 MW baseline wind turbine model. The influence of symmetrical icing in different locations of the blade and asymmetrical icing of the blade assembly is analyzed on the turbine’s dynamic behavior using the aeroelastic computer-aided engineering tool FAST. The outer third of the blade produces about 50% of the turbine’s total power and severe icing in this part of the blade reduces power output and aeroelastic damping of the blade’s flapwise vibration modes. The increase in blade mass due to ice reduces its natural frequencies which can be extracted from the vibration responses of the turbine operating under turbulent wind conditions. Symmetrical icing of the blades reduces loads acting on the turbine components, whereas asymmetrical icing of the blades induces loads and vibrations in the tower, hub, and nacelle assembly at a frequency synchronous to rotational speed of the turbine.

sted, utgiver, år, opplag, sider
MDPI, 2019
Emneord
wind turbine, icing, simulation, aeroelastic behavior, CFD
HSV kategori
Forskningsprogram
Datorstödd maskinkonstruktion; Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-71180 (URN)10.3390/en12122422 (DOI)000473821400195 ()
Merknad

Validerad;2019;Nivå 2;2019-07-05 (johcin)

Tilgjengelig fra: 2018-10-12 Laget: 2018-10-12 Sist oppdatert: 2019-10-21bibliografisk kontrollert
5. Wind Turbine Aerodynamic Modeling in Icing Condition: Three-Dimensional RANS-CFD Versus Blade Element Momentum Method
Åpne denne publikasjonen i ny fane eller vindu >>Wind Turbine Aerodynamic Modeling in Icing Condition: Three-Dimensional RANS-CFD Versus Blade Element Momentum Method
2019 (engelsk)Inngår i: Journal of energy resources technology, ISSN 0195-0738, E-ISSN 1528-8994, Vol. 141, nr 7, artikkel-id 071201Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Icing limits the performance of wind turbines in cold climates. The prediction of the aerodynamic performance losses and their distribution due to ice accretion is essential. Blade element momentum (BEM) is the basis of blade structural studies. The accuracy and limitations of this method in icing condition are assessed in the present study. To this purpose, a computational study on the aerodynamic performance of the full-scale NREL 5 MW rotor is performed. Three-dimensional (3D) steady Reynolds-averaged Navier–Stokes (RANS) simulations are performed for both clean and iced blade, as well as BEM calculations using two-dimensional (2D) computational fluid dynamics (CFD) sectional airfoil data. The total power calculated by the BEM method is in close agreement with the 3D CFD results for the clean blade. There is a 4% deviation, while it is underestimated by 28% for the iced one. The load distribution along the clean blade span differs between both methods. Load loss due to the ice, predicted by 3D CFD, is 32% in extracted power and the main loss occurs at the regions where the ice horn height exceeds 8% of the chord length.

sted, utgiver, år, opplag, sider
ASME, 2019
HSV kategori
Forskningsprogram
Strömningslära; Datorstödd maskinkonstruktion
Identifikatorer
urn:nbn:se:ltu:diva-73824 (URN)10.1115/1.4042713 (DOI)000470845800013 ()2-s2.0-85063888524 (Scopus ID)
Merknad

Validerad;2019;Nivå 2;2019-05-03 (johcin)

Tilgjengelig fra: 2019-05-03 Laget: 2019-05-03 Sist oppdatert: 2020-01-07bibliografisk kontrollert
6. Uncertainty quantification of iced airfoil  on wind Turbine Using polynomial chaos expansion
Åpne denne publikasjonen i ny fane eller vindu >>Uncertainty quantification of iced airfoil  on wind Turbine Using polynomial chaos expansion
2018 (engelsk)Inngår i: Journal of energy resources technology, ISSN 0195-0738, E-ISSN 1528-8994Artikkel i tidsskrift (Fagfellevurdert) Submitted
HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-71182 (URN)
Tilgjengelig fra: 2018-10-12 Laget: 2018-10-12 Sist oppdatert: 2018-10-16

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