Erosion test - Maximize service life of your wind turbine blades

Erosion test | DNV-RP-0171

Wind turbine blades are continuously exposed to UV rays from the sun, as well as to a constant barrage of rain drops, grains of sand, dust particles, hail, insects and more. The protective properties of the surface are therefore crucial to the service life of the blade – especially on the leading edge, which bears the brunt of the impacts.

It is essential to choose the best possible surface so as to maximise service life, fulfil warranty obligations and control costs.

Erosion tests of the highest quality

Polytech has two accredited test centers in Denmark. At our center in Bramming, we perform erosion tests on wind turbine blades in accordance with the latest recommended practice: DNV-RP-0171.

The test is designed to establish the durability of the protective layer on the leading edge.

It is possible to combine the erosion test with an accelerated weathering test, such as ISO 20340 (Simulation of impacts in offshore environment).

Procedure for erosion test DNV-RP-0171

1. The customer receives test profiles in fibreglass-reinforced polymer (FRP)
2. The customer applies the leading edge protection product
3. The customer sends the coated test profiles to Polytech
4. The test profiles are installed in the test machine
5. The profiles are accelerated to the speed designated by the customer (typically a blade tip speed of 160 m/s).
6. The “rain” is started and the test begins
7. On request, the test can be interrupted at pre-defined intervals to collect photo documentation of the development of the erosion
8. Data and photos from the test are collated in a Test Report.

Variable test parameters

• Raindrop size: 2–2.5 mm or 3–3.5 mm
• Precipitation volume: 29–56 mm/hour
• Water temperature: 4°C–30°C
• Speed: 63–173 m/s
• Intervals between photo documentation
• Duration of test and sequences
  
  

Photo options

• Automatic high-resolution (20 MP) photos at defined intervals
• Manual high-resolution photos
• Manual high-resolution photos with high contrast

 

We calibrate our test equipment in accordance with DNVGL-RP-0171 whenever critical parameters are changed, as well as at fixed, predefined intervals.

Recommended evaluation of test results

The pictures from an erosion test can be converted into a graph by measuring the development of the erosion (mm) in each interval and plotting them in. On comparison of several tests, the leading edge protection with the shallowest slope will be the most resistant to erosion.

Two valid parameters for the development of erosion are:

• incubation time (time before erosion becomes apparent on the leading edge)
• breakthrough time (time before erosion has completely broken through the material tested)

Independent third-party tests

The Polytech Test Center is accredited by DANAK in accordance with the ISO 17025 standard and operates as an independent test institute.

Contact us for additional information.

Rain Erosion Test
See our state-of-the-art rain erosion system in action.