Numerical Simulations of Aerodynamic Feature for Variable Speed Offshore Wind Turbine

2011 ◽  
Vol 52-54 ◽  
pp. 1556-1559
Author(s):  
Ping He ◽  
Nai Chao Chen ◽  
Dan Mei Hu
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Gas Flow ◽  
Rapid Change ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Total Force ◽  
Variable Speed ◽  
Horizontal Axis Wind Turbine ◽  
Blade Height

The liquid-gas flow is proposed to accurately simulate the offshore environmental state. The aerodynamic feature is estimated using the three-dimensional model of horizontal-axis wind turbine with NRELS809 series aerofoil by means of the simulating software tool of FLUENT. The variable speed is implemented via the six different wind speeds. The calculated results show that the similarly evolutional tendency of velocity occurs in the wake region when operating at the six variable speeds. The stall speed is related to blade height and wind speed. The small blade height or large wind speed also leads to the serious stall phenomenon. The total force is conducted to estimate the potential capability for leeward and windward surface to capture wind power. The calculated results reveal that the larger wind speed facilitates generating the more magnitude of total force. However, the velocity and force feature for the wind turbine has the especially rapid change at the wind speed of 6 m/s, which perhaps results from the intrinsic geometry and configuration.

Modeling and Analysis of an Offshore Wind Turbine With Fluid Power Transmission for Centralized Electricity Generation

2015 ◽  
Vol 10 (4) ◽  
Author(s):  
Antonio Jarquin Laguna
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Electricity Generation ◽  
Passive Control ◽  
Power Transmission ◽  
Torque Control ◽  
Fluid Power ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Variable Speed

This paper presents a mathematical model of an innovative offshore wind turbine with fluid power transmission. The proposed concept is a variable-speed, pitch controlled turbine which differs from conventional technology by using fluid power technology as a medium to transfer the energy from the wind. The final aim is to use several turbines to centralize electricity generation. Unlike conventional variable speed concepts, the proposed turbine comprises a passive-torque control method which allows the turbine to operate at optimal aerodynamic performance for different wind speeds. A numerical model of a single turbine is developed and time-domain simulations are used to analyze the dynamic response of the different operational parameters to a turbulent wind speed input. The results are compared with those of a reference offshore wind turbine with similar characteristics. It is shown that operation below rated wind speed with a passive control is possible for a single turbine with a better dynamic performance than the reference in terms of transmission torque. However, the efficiency of the energy transmission is reduced throughout the operational range. The addition and simulation of more turbines to the hydraulic network is necessary to determine to which extent the benefits of a centralized wind farm compensate for the relatively lower efficiency.

scholarly journals Validation of Numerical Models of the Offshore Wind Turbine From the Alpha Ventus Wind Farm Against Full-Scale Measurements Within OC5 Phase III

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Wojciech Popko ◽  
Amy Robertson ◽  
Jason Jonkman ◽  
Fabian Wendt ◽  
Philipp Thomas ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Farm ◽  
Operating Conditions ◽  
Offshore Wind ◽  
Phase Iii ◽  
Offshore Wind Turbine ◽  
Discrete Fourier Transforms ◽  
Simulation Tools ◽  
Axial Forces

Abstract The main objective of the Offshore Code Comparison Collaboration Continuation, with Correlation (OC5) project is validation of aero-hydro-servo-elastic simulation tools for offshore wind turbines (OWTs) through comparison of simulated results to the response data of physical systems. Phase III of the OC5 project validates OWT models against the measurements recorded on a Senvion 5M wind turbine supported by the OWEC Quattropod from the alpha ventus offshore wind farm. The following operating conditions of the wind turbine were chosen for the validation: (1) idling below the cut-in wind speed, (2) rotor-nacelle assembly (RNA) rotation maneuver below the cut-in wind speed, (3) power production below and above the rated wind speed, and (4) shutdown. A number of validation load cases were defined based on these operating conditions. The following measurements were used for validation: (1) strains and accelerations recorded on the support structure and (2) pitch, yaw, and azimuth angles, generator speed, and electrical power recorded from the RNA. Strains were not directly available from the majority of the OWT simulation tools; therefore, strains were calculated based on out-of-plane bending moments, axial forces, and cross-sectional properties of the structural members. The simulation results and measurements were compared in terms of time series, discrete Fourier transforms, power spectral densities, and probability density functions of strains and accelerometers. A good match was achieved between the measurements and models setup by OC5 Phase III participants.

At Sea Experiment of a Hybrid Spar for Floating Offshore Wind Turbine Using 1/10-Scale Model

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Tomoaki Utsunomiya ◽  
Hidekazu Matsukuma ◽  
Shintaro Minoura ◽  
Kiyohiko Ko ◽  
Hideki Hamamura ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Prestressed Concrete ◽  
Cost Effective ◽  
Offshore Wind ◽  
Scale Model ◽  
Offshore Wind Turbine ◽  
Prototype Model ◽  
Horizontal Axis Wind Turbine ◽  
Floating Offshore Wind Turbine ◽  
Level 3

This study aims at development of a cost-effective, floating offshore wind turbine. The prototype model considered herein is composed of (1) 2-MW horizontal-axis wind turbine (HAWT) of downwind type, (2) steel monotower with 55-m hub height above sea level, (3) steel-prestressed concrete (PC) hybrid SPAR-type foundation with 70-m draft, and (4) catenary mooring system using anchor chains. In order to demonstrate the feasibility of the concept, an at-sea experiment using a 1/10-scale model of the prototype has been made. The demonstrative experiment includes (1) construction of the hybrid SPAR foundation using PC and steel, the same as the prototype; (2) dry-towing and installation to the at-sea site at 30-m distance from the quay of the Sasebo shipbuilding yard; (3) generating electric power using a 1 kW HAWT; and (4) removal from the site. During the at-sea experiment, wind speed, wind direction, tidal height, wave height, motion of the SPAR, tension in a mooring chain, and strains in the tower and the SPAR foundation have been measured. Motion of the SPAR has been numerically simulated and compared with the measured values, where basically good agreement is observed.

Load Reduction on Offshore Wind Turbines by Aerodynamic Flaps

2017 ◽  
Author(s):  
Shilpa Thakur ◽  
Nilanjan Saha
Keyword(s):  
Wind Turbine ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Load Reduction ◽  
Horizontal Axis Wind Turbine ◽  
Trailing Edge ◽  
Hydrodynamic Loads ◽  
Trailing Edge Flaps ◽  
Unsteady Effects ◽  
Bem Theory

This paper focuses on load reduction by implementing controllable trailing-edge flaps on an offshore wind turbine (OWT) supported on different fixed bottom structures in various water depths. The benchmark NREL 5-MW offshore horizontal axis wind turbine is used as a reference. This work utilizes the wind turbine simulation tool FAST with coupled stochastic aerodynamic-hydrodynamic analysis for obtaining the responses. The flap is controlled using an external dynamic link library through PID controller. Blade element momentum (BEM) theory and Morison equation are used to compute the aerodynamic and hydrodynamic loads, respectively. BEM theory is presently modified to account for unsteady effects of flaps along the blade span. Variation in force coefficients is shown due to unsteady effects of flaps. The present analysis results show reduction up to 8–29% in blade loads for the turbine with different support structures on implementing controllable trailing edge flaps. Also, an influence of blade load reduction on tower base and nacelle is shown. Tower loads are calculated considering aerodynamic and hydrodynamic loads individually. This study can form the basis for evaluating the performance for large-scale fixed offshore wind turbine rotors.

A New Simulation and Control Model for a Variable Speed Variable Pitch Direct Drive Large Offshore Wind Turbine Generator With Integrated Energy Storage

2014 ◽  
Author(s):  
B. Kazemtabrizi ◽  
S. Hogg
Keyword(s):  
Energy Storage ◽  
Wind Speed ◽  
Wind Turbine ◽  
Offshore Wind Turbine ◽  
Maximum Output ◽  
Variable Speed ◽  
Turbine Generator ◽  
Super Capacitor ◽  
Variable Pitch ◽  
Wind Turbine Generator

A comprehensive control and simulation model has been presented in this paper for a large multi-megawatt Variable Speed Variable Pitch Wind Turbine Generator (WTG) with Energy Storage System (ESS) integration. The generator is of a Permanent Magnet Synchronous Generator (PMSG) type which is then decoupled from the grid using a Fully-Rated back-to-back Converter (FRC) link. A Rotor Flux Oriented Control (RFOC) strategy has been adopted in order to extract the maximum output electromagnetic torque from the generator according to a Maximum Power Point Tracking (MPPT) profile for any wind speed lower than rated wind speed. The MPPT method presented in this paper relies on the turbine’s optimal output torque curve. The ESS makes provisions for enhanced performance especially during faults on the system. Dynamic performance of a super-capacitor makes it ideal as the integrated ESS in the WTG for satisfying such performance constraints. Results indicate that the WTG integrated with a super-capacitor ESS provides the required enhanced performance in terms of DC link voltage stability and limiting output power fluctuations during sudden variations in the wind speed as well as enhanced Fault Ride-Through (FRT) capability.

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