ICE^2 · ICEphobicity for severe ICing Environments
FP7 — People (Marie Curie Actions)
- Duration
- 2012-09-01 → 2014-11-30
- EU contribution
- €192,622
- Participants
- 1
- Scheme
- MC-IEF
Lines connect the coordinator with its partners.
Results in brief
ICEphobicity for severe ICing Environments
The present report briefly summarizes the research project achievements, which are discussed in more details in the two periodic reports for the two periods: 1) September 2012 - November 2013, and 2) November 2013 – November 2014. • WP1: Supercooled drop impact on dry, pre-wetted and iced surfaces. A new state-of the-art icing apparatus has been developed at LTNT (Laboratory of Thermodynamics in Emerging Technologies) headed by Prof. Poulikakos (scientist in charge), to study impact of supercooled drops in severely supercooling conditions. The problem of supercooled water drops impacting on superhydrophobic textures for drop supercooling down to −17 °C was investigated, to find that increased viscous effects significantly influence all stages of impact dynamics, and in particular, the impact and meniscus impalement behavior, with severe implications to water retention by the textures (sticky versus rebounding drop) and possible icing. In addition, a specific study on liquid meniscus penetration into the microtexture was also performed using X-ray during a test campaign at the Paul Scherrer Institute (Switzerland) synchrotron. • WP2: Ice crystal impact on dry, pre-wetted and iced surfaces. An innovative drop handling system, based on acoustic levitation, was recently developed, optimized and integrated in the icing apparatus to generate not only extremely supercooled drops, even below -20°C (thus extending the test conditions reached using a classical pendant drop dispenser as developed in WP1), but also ice crystals and ice-liquid mixtures. Impact tests were conducted on superhydrophobic surfaces to observe different scenarios, including ice crystal formation at the moment of impact due to instantaneous nucleation of extremely supercooled drops, as well as inhibition of drop rebound in case of partially frozen drop (i.e., liquid-ice mixture) on superhydrophobic surfaces, identifying that ice crystals can stick to surfaces in the presence of liquid water, due to capillary adhesion effects. • WP3: Design and production of functionalized surfaces. Together with specific micro- and nano-engineered surfaces, which were specifically designed and fabricated on silicon based surfaces to conduct supercooled drop and ice crystal experiment, the problem of surface durability under adverse conditions was addressed. By superposing selected hydrophobic layers (i.e. self-assembled monolayers, thin films, or nanofibrous coatings) on hierarchically textured aluminum surfaces, a surface that simultaneously exhibit excellent chemical stability, mechanical durability and droplet impalement resistance was developed and fabricated. Additional multi-functional superhydrophobic surfaces were developed using polymer nano-composites, providing to the solid surface not only the non-wetting properties, but also high electrical conductivity. For more details see http://www.ltnt.ethz.ch/
Data: CORDIS, © European Union
Project objective
Icing on structures represents a severe risk for human safety and has a significant economic impact on operation costs in many different areas such as aeronautics, power systems (e.g. wind turbines and electric power transmission lines), civil construction (e.g. bridges) and oil platforms to name a few. US National Transportation Safety Board (NTSB) estimates that each year there are about 30 icing related accidents in aeronautics in the US alone.Although icing research has a long tradition, there is a need to investigate the fundamental mechanisms of ice accretion, to improve the prediction of ice accumulation due to supercooled drops and ice crystals, which can adhere to cold surfaces and cause ice accumulation, and to develop effective ice protection systems. Impact of supercooled drops and ice crystals is particularly relevant to icing in severe icing conditions such as the ones with high degree of supercooling. The new proposed standards from Federal Aviation Administration published in June 2010 also recognize this as a very important problem. Therefore, the aim of the proposed project is to advance the fundamental science base on the dynamics and the phase change phenomena in severely supercooled drops and ice crystals interacting with surfaces and to define a new norm for icephobicity. Carefully designed supercooled drop and ice crystal impact experiments on solid surfaces with different texture and wettability are proposed as a means to develop the required understanding of ice adhesion. Through optimal choice of surface properties and results of impact experiments, the project will focus on developing so called icephobic surfaces, which should form the basis for a highly promising coating strategy to combat ice accumulation on surfaces by minimizing ice adhesion and increase the efficiency of present anti-icing systems.""
Original text from CORDIS.
Participants
- EIDGENOESSISCHE TECHNISCHE HOCHSCHULE ZUERICH · ZuerichCoordinatorSwitzerland
Links
Data: CORDIS, © European Union