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"Innovation for a brighter future"
Launched August 2020

OGAB® Air edge® virtual feathering

Our Air Edge® wind turbine technology significantly reduces maintenance time and cost by protecting the turbine blades from weather damage through a unique Virtual Feathering solution. The method utilises active aerodynamics to protect the surface of the blades with a layer of air.

Protecting wind turbine blades from the damage caused by the outside elements with our innovative Virtual Feathering technology.

Wind turbines often suffer from severe leading edge erosion after being in service for a period of time. Such erosion has escalated the concerns about the reliability of the wind turbines in relation to their operation in the long-term. Leading edge erosion also causes performance deterioration and additional maintenance costs. Furthermore, it also results in a substantial increase in the blade’s surface roughness and affects the aerodynamics of the flow around the blades, which has a detrimental effect on the wind turbine’s efficiency. 

It has been reported that heavily eroded wind turbine blades can decrease the annual energy production by up to 5% in an industrial scale wind turbine. This phenomenon originates from the nature of the harsh environment that the wind turbines operate in. As the wind turbine blade slices through the wind at high speeds, the fine particulate in the air, such as dust, ice, raindrops, hailstorm and snow, smash into the blade’s surface.  Eventually, over time, these tiny collisions wear away the coating layer of the wind turbine blade surface and penetrate deeper into the blades. 

Although the rotational speed of the wind turbines are not significant, due to their very long blades their tip speeds are extremely high (in the range of 190-290 km/hr). This means that the collisions between rain droplets and blades are excessively abrasive. It’s not just leading edge erosion that reduces efficiency, but also dielectric charges that lead to greater lightning damage as well as other aspects of wear and tear.

Reducing labour, maintenance costs and operational downtime.

The goal in operating wind turbine plants is to keep their aerodynamic characteristics for as long as possible in line with their original factory conditions. With the expectation of the long service life of the renewable energy harvesting technologies, maintaining such conditions for 20 years is crucial and demanding. 

Wind turbine manufacturers are still lagging behind in tackling this problem. While there have been some endeavours in this regard by retrofitting older blades with leading edge protection methods using tape, paste, epoxy and metal tiles, there has, until now, not been an effective protection method of the wind turbine blade leading edge.

Our breakthrough Air Edge® technology testing gives the solution to improve leading edge erosion rate in wind turbines by 47%. 

The figures below show the erosion rate on both test cases – with and without virtual feathering. As evident from figure below, a significant erosion rate exists across the leading edge of the wind turbine. This situation is more severe across the blade tip, where the tip speed is significantly higher. 

Test case without Virtual Feathering.

In addition to this, without virtual feathering, the erosion is not only limited to the leading edge but also over the suction surface of the blade where there is significant erosion. The situation is milder on the pressure surface of the case without virtual feathering. 

On the contrary, for the case with virtual feathering (Figure 13) there have been remarkable improvements in the blade erosion rate. Due to the implementation of our technology, the majority of the erosion has been eliminated on the pressure surface while the severity of the erosion on the suction surface is significantly reduced. Overall, the affected areas have been reduced substantially as a result of applying the proposed virtual feathering concept to the leading edge of the wind turbine. 

 

Test case with Virtual Feathering implemented.

It is evident from the presented results that the proposed virtual feathering was an effective solution to the wind turbine erosion problem. It was possible to decrease the erosion rate of the wind turbine blade by about 47%. However, this should be noted that such improvement was achieved for the case of water droplets of a particular size and mass flow rate only. The erosion rate can have higher or lower severity under snow or hail storms of different mass flow rates. However, in a relative perspective, we can conclude that the virtual feathering can extend the service life of the wind turbines as well as reducing the maintenance cost and alleviating safety concerns.

Get in touch today to find out more about how our Air Edge® technology can help you.