Computation of Aerodynamic Performance Deterioration of Wind Turbine Blade Due to Ice Accretion

Author(s):  
Kousuke Nushi ◽  
Shingo Kasai ◽  
Kazuyuki Toda ◽  
Makoto Yamamoto ◽  
Makoto Iida ◽  
...  

The attention for a wind power-generator has been attracted as one of the solutions for the environmental problems. When a wind turbine is operated in winter, supercooled water droplets impinge on the blade surface, and as the result ice accretes around the leading edge. It is well known that the occurrence of ice accretion on the wind turbine blade can lead to the severe deterioration of aerodynamic performance. However, the experiment is difficult, because it is not easy to create repeatedly the accretion conditions in a laboratory. Therefore, CFD is expected as a useful tool to predict and investigate the phenomena. In the present study, we develop the ice accretion code, and apply it to the MEL wind turbine blade. From the computational results, the shape of the ice-accreted blade and the deterioration of aerodynamic performance are numerically investigated.

Author(s):  
D. S. Swasthika ◽  
Mahesh K. Varpe

Abstract In wind turbine blade, most of the losses occurs due to aerodynamic losses in the post stall operating condition. Adoption of the blade leading edge tubercles improves the post stall aerodynamic performance. Nevertheless the geometric parameters of the protuberance play a vital role in influencing the aerodynamic performance, it is possible that shape of the protuberance may also have aerodynamic significance. In this paper different types of tubercle shapes are adopted on the blade leading edge to study the improvement in the aerodynamic performance. Each of the shape is studied for different AOA operating at Reynolds number of 3 × 105. The results revealed that the shape of the tubercles also influence the flow which affects the performances.


2017 ◽  
Vol 863 ◽  
pp. 229-234
Author(s):  
Muhammad S. Virk

A multiphase numerical study has been carried out to understand the effects of wind turbine blade profile (airfoil) symmetry on resultant ice accretion. Two symmetric (NACA 0006 & 0012) and two non-symmetric airfoils (NACA 23012 & N-22) were used for this preliminary study. Based upon the airflow field calculations and super cooled water droplets collision efficiency, the rate and shape of accreted ice was simulated for rime ice conditions. Analysis showed higher air velocity along top surface of the non-symmetric airfoils as compared to symmetrical airfoils that also effects the droplet behavior and resultant ice growth. Results show that change in blade profile symmetry effects the resultant ice accretion. For symmetric airfoils, more streamlines ice shapes were observed along leading edge as compared to non- symmetric airfoils.


Author(s):  
GholamHossein Maleki ◽  
Ali Reza Davari ◽  
Mohammad Reza Soltani

An extensive experimental investigation was conducted to study the effects of Dielectric Barrier Discharge (DBD), on the flow field of an airfoil at low Reynolds number. The DBD was mounted near the leading edge of a section of a wind turbine blade. It is believed that DBD can postpone the separation point on the airfoil by injecting momentum to the flow. The effects of steady actuations on the velocity profiles in the wake region have been investigated. The tests were performed at α = 4 to 36 degrees i.e. from low to deep stall angles of attack regions. Both surface pressure distribution and wake profile show remarkable improvement at high angles of attack, beyond the static stall angle of the airfoil when the plasma actuation was implemented. The drag calculated from the wake momentum deficit has further shown the favorable role of the plasma actuators to control the flow over the airfoil at incidences beyond the static stall angle of attack of this airfoil. The results demonstrated that DBD has been able to postpone the stall onset significantly. It has been observed that the best performance for the plasma actuation for this airfoil is in the deep stall angles of attack range. However, below and near the static stall angles of attack, plasma augmentation was pointed out to have a negligible improvement in the aerodynamic behavior.


2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Alvaro Gonzalez ◽  
Xabier Munduate

This work undertakes an aerodynamic analysis over the parked and the rotating NREL Phase VI wind turbine blade. The experimental sequences from NASA Ames wind tunnel selected for this study respond to the parked blade and the rotating configuration, both for the upwind, two-bladed wind turbine operating at nonyawed conditions. The objective is to bring some light into the nature of the flow field and especially the type of stall behavior observed when 2D aerofoil steady measurements are compared to the parked blade and the latter to the rotating one. From averaged pressure coefficients together with their standard deviation values, trailing and leading edge separated flow regions have been found, with the limitations of the repeatability of the flow encountered on the blade. Results for the parked blade show the progressive delay from tip to root of the trailing edge separation process, with respect to the 2D profile, and also reveal a local region of leading edge separated flow or bubble at the inner, 30% and 47% of the blade. For the rotating blade, results at inboard 30% and 47% stations show a dramatic suppression of the trailing edge separation, and the development of a leading edge separation structure connected with the extra lift.


Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3330 ◽  
Author(s):  
Jianhua Xu ◽  
Zhonghua Han ◽  
Xiaochao Yan ◽  
Wenping Song

A new airfoil family, called NPU-MWA (Northwestern Polytechnical University Multi-megawatt Wind-turbine A-series) airfoils, was designed to improve both aerodynamic and structural performance, with the outboard airfoils being designed at high design lift coefficient and high Reynolds number, and the inboard airfoils being designed as flat-back airfoils. This article aims to design a multi-megawatt wind turbine blade in order to demonstrate the advantages of the NPU-MWA airfoils in improving wind energy capturing and structural weight reduction. The distributions of chord length and twist angle for a 5 MW wind turbine blade are optimized by a Kriging surrogate model-based optimizer, with aerodynamic performance being evaluated by blade element-momentum theory. The Reynolds-averaged Navier–Stokes equations solver was used to validate the improvement in aerodynamic performance. Results show that compared with an existing NREL (National Renewable Energy Laboratory) 5 MW blade, the maximum power coefficient of the optimized NPU 5 MW blade is larger, and the chord lengths at all span-wise sections are dramatically smaller, resulting in a significant structural weight reduction (9%). It is shown that the NPU-MWA airfoils feature excellent aerodynamic and structural performance for the design of multi-megawatt wind turbine blades.


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