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The effect of temperature on the erosion of polyurethane coatings for wind turbine leading edge protection

The effect of temperature on the erosion of polyurethane coatings for wind turbine leading edge protection
The effect of temperature on the erosion of polyurethane coatings for wind turbine leading edge protection
Wind turbine leading-edge erosion can degrade the aerodynamic properties of blades and reduce their efficiency. Previous theoretical work has suggested that low temperatures might affect the erosion performance of leading-edges and protective leading-edge coatings. Solid particle erosion is caused by dust, sand and hailstones impacting the leading edges. For polymer coatings, temperature is a particular concern; the low temperatures can cause a transition from ductile to brittle failures. Polyurethane (PU) coatings were eroded at two temperatures: ambient (25°C) and cold (-30°C). An adapted solid-air erosion facility was used to accelerate sub-angular sand particles of 96.2 µm mean size to a velocity of 68±8 m/s. Low volumetric sand concentrations of 1.3×10-4 % were studied at two impingement angles of 45 and 90 degrees. The results showed that cold temperatures influenced the erosion rate and erosion mechanism of the coatings, with the erosion rate at the cold temperature increasing significantly. The erosion classification values and the shape of the wear scar suggested plastic erosion behaviour of the PU at cold temperatures, as opposed to the more erosion-resistant elastic behaviour. A temperaturecontrolled nanoindentation study demonstrated that the ratio of hardness to modulus reduced and the plasticity index increased with a reduction in temperature, implying the PU coatings had an increased propensity to plastically deform during cold erosion. This supports the erosion performance seen in experiments; however, the cold erosion surfaces developed more pits than the ambient case. Crosssection analysis of the eroded coatings showed accumulation of damage subsurface with evidence of delamination at the weakest interfaces in the layered coating systems, across all temperatures.
Polymers, Coatings, Solid particle erosion, Nanoindentation, Profilometry, Wind turbines
0043-1648
Godfrey, Mike
64cac3da-67a6-4ab1-82de-233cc6e47ce9
Siederer, Oliver
aa903648-78f1-4892-b7f7-f2d6e8d4a49b
Zekonyte, Jurgita
c40df725-5ce3-4692-b638-bbb4d847b5ea
Barbaros, Ismail
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Wood, Robert
d9523d31-41a8-459a-8831-70e29ffe8a73
Godfrey, Mike
64cac3da-67a6-4ab1-82de-233cc6e47ce9
Siederer, Oliver
aa903648-78f1-4892-b7f7-f2d6e8d4a49b
Zekonyte, Jurgita
c40df725-5ce3-4692-b638-bbb4d847b5ea
Barbaros, Ismail
01c31af6-da0e-4aa8-b1c4-8faafd0b277e
Wood, Robert
d9523d31-41a8-459a-8831-70e29ffe8a73

Godfrey, Mike, Siederer, Oliver, Zekonyte, Jurgita, Barbaros, Ismail and Wood, Robert (2021) The effect of temperature on the erosion of polyurethane coatings for wind turbine leading edge protection. Wear, 476, [203720]. (doi:10.1016/j.wear.2021.203720).

Record type: Article

Abstract

Wind turbine leading-edge erosion can degrade the aerodynamic properties of blades and reduce their efficiency. Previous theoretical work has suggested that low temperatures might affect the erosion performance of leading-edges and protective leading-edge coatings. Solid particle erosion is caused by dust, sand and hailstones impacting the leading edges. For polymer coatings, temperature is a particular concern; the low temperatures can cause a transition from ductile to brittle failures. Polyurethane (PU) coatings were eroded at two temperatures: ambient (25°C) and cold (-30°C). An adapted solid-air erosion facility was used to accelerate sub-angular sand particles of 96.2 µm mean size to a velocity of 68±8 m/s. Low volumetric sand concentrations of 1.3×10-4 % were studied at two impingement angles of 45 and 90 degrees. The results showed that cold temperatures influenced the erosion rate and erosion mechanism of the coatings, with the erosion rate at the cold temperature increasing significantly. The erosion classification values and the shape of the wear scar suggested plastic erosion behaviour of the PU at cold temperatures, as opposed to the more erosion-resistant elastic behaviour. A temperaturecontrolled nanoindentation study demonstrated that the ratio of hardness to modulus reduced and the plasticity index increased with a reduction in temperature, implying the PU coatings had an increased propensity to plastically deform during cold erosion. This supports the erosion performance seen in experiments; however, the cold erosion surfaces developed more pits than the ambient case. Crosssection analysis of the eroded coatings showed accumulation of damage subsurface with evidence of delamination at the weakest interfaces in the layered coating systems, across all temperatures.

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WOM2021-D-20-00007 - Accepted Manuscript
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More information

Accepted/In Press date: 11 January 2021
e-pub ahead of print date: 24 February 2021
Published date: 15 July 2021
Keywords: Polymers, Coatings, Solid particle erosion, Nanoindentation, Profilometry, Wind turbines

Identifiers

Local EPrints ID: 446733
URI: http://eprints.soton.ac.uk/id/eprint/446733
ISSN: 0043-1648
PURE UUID: 30c4b5f9-3e84-4fd3-a000-266c46bcfb50
ORCID for Mike Godfrey: ORCID iD orcid.org/0000-0002-6655-6437
ORCID for Robert Wood: ORCID iD orcid.org/0000-0003-0681-9239

Catalogue record

Date deposited: 19 Feb 2021 17:31
Last modified: 17 Mar 2024 06:15

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Contributors

Author: Mike Godfrey ORCID iD
Author: Oliver Siederer
Author: Jurgita Zekonyte
Author: Ismail Barbaros
Author: Robert Wood ORCID iD

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