Definition of Best Practice for Testing Icephobic Surfaces
rehfeld, nadine; Godreau, Charles; hou, xianghui; Kim, Taeseong; Koss, Holger; He, Jianying; Rittinghaus, Claas
Research report
Published version
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https://hdl.handle.net/11250/3045172Utgivelsesdato
2022Metadata
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Sammendrag
Wind energy in Cold Climates needs to address various technical aspects in order to avoid lower energy production and liability issues, such as ice throw and noise. “Active” ice protection systems (mainly heating) for the rotor blades of the turbines were one of the first important technical steps to cope with icing phenomenon on surfaces. The use of so-called icephobic surfaces (referred to as “passive” ice protection in this report) appeared to be even more desirable, as the overall prevention of ice formations would solve many of the technical problems related to icing. However, the broad range of relevant icing conditions, the different icing scenarios the blade areas are facing at, and the harsh environmental conditions (UV, rain and particle erosion) combined with the required long-term performance of the material have so far prevented the integration of potential icephobic materials. Despite the high obstacles the icephobic surfaces need to overcome, material developers are still convinced to achieve significant improvements for future coating and surface solutions. One of the most recent solution is to combine heating systems with icephobic materials in hybrid systems to significantly reduce the energy consumption of the heating system. Experiences from more than 20 years of work is available, not only related to the materials itself, but also to the testing strategies for efficient development processes (from low level laboratory tests to complex and expensive field tests). This report summarizes parts of the experiences related to tests for icephobic surfaces. It is not intending to be exhaustive in the list of tests that have ever been used by different researchers. But it summarizes basic test designs with regard to lab based ice formation and ice adhesion tests, ice wind tunnel tests and field test campaigns for icephobic materials. It also highlights the need to address the material durability at an early stage of development, considering relevant ageing scenarios for rotor blade surfaces. This shall avoid premature expectations that finally cannot be met by the coating materials for rotor blade applications. Addition to the test designs and durability aspects, surface properties relevant for the icephobic performance are addressed in this report. This is not only necessary to improve the basic understanding on the icephobic performances of surfaces, but also to identify appropriate monitoring tools and ageing models for the intended application. This aspect is also included in the final recommendations and future needs that are necessary to further improve the testing strategies of icephobic surfaces for rotor blade applications.