{{Short description|Form of materials wear}}
[[File:Water Droplet Erosion Damage in a Steam Turbine Blade.png|thumb|upright=2.0|Water droplet erosion damage in a steam turbine blade]] '''Water droplet erosion (WDE)''' is "a form of [[wear|materials wear]] that is caused by the impact of [[liquid]] droplets with sufficiently high speed."<ref>{{Cite journal|doi=10.1115/1.1523360|title=Introduction to Tribology|year=2003|last1=Bhushan|first1=B.|last2=Ko|first2=Pak Lim|journal=Applied Mechanics Reviews|volume=56|issue=1|pages=B6–B7|bibcode=2003ApMRv..56B...6B|doi-access=free}}</ref> The phenomenon was furthermore previously known as '''liquid impingement erosion (LIE)'''.
==Distinction from other phenomena== The emphasis of discrete [[water droplet]]s serves to distinguish the WDE problem from liquid jet erosion and cavitation. The impact pressures invoked by discrete water droplet impact have a range considerably higher than the stagnation pressure created by liquid jet.
The difference between WDE and [[cavitation erosion]] is the fact that WDE usually comprises a [[gas]]eous or [[vapor]]ous phase containing discrete liquid droplets; while cavitation erosion is observed when a continual liquid phase carries separate gaseous bubbles or cavities inside it.<ref>{{Cite book|chapter-url=https://doi.org/10.31399/asm.hb.v18.a0006378|doi = 10.31399/asm.hb.v18.a0006378|chapter = Liquid Impingement Erosion[1]|title = Friction, Lubrication, and Wear Technology|year = 2017|pages = 302–312|isbn = 978-1-62708-192-4|last1 = Wood|first1 = Robert J.K.}}</ref>
Recently, Ibrahim & Medraj developed an [[model|analytical model]] to predict the threshold speed of water droplet erosion and verified it experimentally, a challenge having been attempted hitherto without success since the 1950s.<ref>{{cite journal|title=Prediction and experimental evaluation of the threshold velocity in water droplet erosion|author=Ibrahim and Medraj|journal=Materials & Design|year=2022|volume=213|article-number=110312|publisher=Elsevier|doi=10.1016/j.matdes.2021.110312|doi-access=free}}</ref>
==Consequences== [[File:Leading edge damage - windturbine.jpg|thumb|left|Water droplet erosion damage in wind turbines caused by rain]] For an extended period of time, many industries have encountered the problem of erosion due to water droplet impact, and it continues to reappear wherever [[rotation]] or [[motion|movement]] of a component at high speed in a [[hydrometer]] environment is employed. Recently, with the use of larger wind [[turbine]] blades, the issue of erosion of the leading edge due to rain droplets has grown more grave. [[Aerodynamic]]s efficiency of [[turbine blades]] is severely diminished due to leading-edge erosion, resulting in a considerable decrease in annual [[energy]] production.<ref name="Water Droplet Erosion of Wind Turbine Blades: Mechanics, Testing, Modeling and Future Perspectives">{{Cite journal|title=Water Droplet Erosion of Wind Turbine Blades: Mechanics, Testing, Modeling and Future Perspectives|year=2019|doi=10.3390/ma13010157|doi-access=free|last1=Elhadi Ibrahim|first1=Mohamed|last2=Medraj|first2=Mamoun|journal=Materials|volume=13|issue=1|page=157|pmid=31906204|pmc=6982018|bibcode=2019Mate...13..157E}}</ref>
==References== {{Reflist}}
[[Category:Materials degradation]]
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