Centrifugal ice adhesion testing combined with heating as de-icing method.

Abstract

Heating is used as a de-icing method in different applications, e.g., in blades of the wind turbines and wings of the airplanes. In many cases, de-icing needs to be done quickly and easily because stopping operation or needs for external maintenance caused by icing increase costs and service time as well as weaken safety issues. Ice on the critical surfaces needs to be removed by using external energy or motion. However, more passive solutions are under development. For this, surface engineering can offer surface and coating solutions, which have icephobic properties and can be used to weaken an ice adhesion between ice and surface. Additionally, one interesting solution is to combine heating as de-icing together with icephobic coatings as anti-icing to achieve multifunctional performance for icing protection systems. In this research, we focus on the development of centrifugal ice adhesion testing (CAT) combined with heating (H) of the tested surface during testing. This way, the icing properties of different materials and coatings were evaluated to understand the combined influence of heating and surface material on ice removal. In centrifugal ice adhesion testing, ice was accreted on the sample surfaces (area ~30 x 30 mm) in an icing wind tunnel. Different ice types i.e., glaze, mixed glaze and rime ice, can be accreted. Ice adhesion can act as an indicator for icephobicity of the surfaces. If the ice adhesion value is low, the surface is icephobic. Because heating is used as de-icing method and can be combined with the icephobic coatings, we developed the ice adhesion testing to analyze this multifunctional behavior. Electrical heating setup for the CAT was designed to evaluate heating effect on ice adhesion. Samples with accreted ice were placed on the heated sample holder for CAT testing (H-CAT). These H-CAT results were compared to CAT results for investigating heat and material influence separately. Several bulk materials and icephobic coatings were studied in order find out suitable heating concept for different materials and coatings.