Ice type
Ice type can change depending on the icing conditions. Ice types can be divided into three different types: glaze ice, rime ice and mixed ice.
- Glaze is clear, dense, and hard ice. Glaze ice is formed at higher temperatures, from freezing rain.
- Rime ice is white and less dense, and softer. Rime is formed mainly by in-cloud icing, in fog for example.
- Mixed ice is a combination of glaze and rime and has properties from both.
Factors that determine which type of ice is accreted are temperature, icing type, wind speed, air humidity, precipitation type (droplets size distribution and intensity i.e. liquid water content) and phases of water.
Material properties influence ice type as well, like surface topography and chemistry, wetting behavior, and surface temperature. Changing weather parameters, however, will also determine the forming ice type. Roughly speaking when droplets are more tightly together, and freeze slower, they form glaze. When freezing is faster, and droplets are not so well arranged, rime is formed. This is why glaze is denser than rime.
Formation of rime ice differs from other icing due its small droplet size, low temperature and low LWC. [2]
Wet ice (glaze) grows when the water nucleates slowly because the air is warm, drops are large, and liquid water content is high. Air is excluded as the water freezes, and a clear accumulation forms with excess water running off, and perhaps refreezing as icicles. [3]
More on this topic: Ice density
References
- ↑ 1.0 1.1 Stenroos, C. (2015) Properties of icephobic surfaces in different icing conditions. https://www.semanticscholar.org/paper/Properties-of-icephobic-surfaces-in-different-icing-Stenroos/d40a044131114b37dbdb41d793ffc849a765a6d8
- ↑ ISO-12494, Atmospheric icing of structures, 2001, 56 p.
- ↑ Charles C. Ryerson. April 2013. Icing Management for Coast Guard Assets. Cold Regions Research and Engineering Laboratory. ERDC/ C R R E L TR-13-7.
- ↑ Han, P. (2012). Scaled ice accretion experiments on a rotating wind turbine blade. Journal of Wind Engineering and Industrial Aerodynamics, 109, 55–67
- ↑ Farzaneh, M. (2008) Atmospheric Icing of Power Networks. 1st ed. 2008. [Online]. Dordrecht: Springer Netherlands.
- ↑ Ingvaldsen, K. (2017) Atmospheric icing in a changing climate: Impact of higher boundary temperatures on simulations of atmospheric ice accretion on structures during the 2015-2016 icing winter in West-Norway.
- ↑ M. Farzaneh, Atmospheric icing of power networks. Springer, London, United Kingdom, 2008, 381 p.