查看“︁克努森層”︁的源代码

'''克努森層'''（'''Knudsen layer'''）也稱為'''蒸发層'''，是固體或液體上面的一層薄蒸氣層，得名自丹麥科學家[[馬丁·克努森]]。克努森層的厚度約為[[平均自由程]]的數倍<ref>{{cite journal|title=Knudsen Layer for Gas Mixtures|journal=Journal of Statistical Physics|doi=10.1023/a:1023876025363|url=https://link.springer.com/article/10.1023/A:1023876025363|date=2003-08-01|volume=112|issue=3-4|language=en|pages=629–655|issn=0022-4715|accessdate=2018-04-02|author=Kazuo Aoki, Claude Bardos, Shigeru Takata|archive-date=2018-06-02|archive-url=https://web.archive.org/web/20180602122104/https://link.springer.com/article/10.1023%2FA%3A1023876025363|dead-url=no}}</ref>。

==克努森層厚度==
克努森層厚度可以近似為<math>l_c</math><ref>{{cite journal|url=http://aip.scitation.org/doi/10.1063/1.1516211|pages=4242–4255|title=Gas-dynamic boundary conditions of evaporation and condensation: Numerical analysis of the Knudsen layer|journal=Physics of Fluids|volume=14|issue=12|author=Andrey V. Gusarov, Igor Smurov|doi=10.1063/1.1516211|access-date=2018-04-02|archive-date=2022-01-29|archive-url=https://web.archive.org/web/20220129234152/https://aip.scitation.org/doi/10.1063/1.1516211|dead-url=no}}</ref>

<math>l_c =\frac{k T_s}{\pi d^2 p_s}</math>,

其中
:<math>k</math>為[[波茲曼常數]]。
:<math>T_s</math>為溫度。
:<math>d</math>為分子直徑。
:<math>p_s</math>為壓力。

==應用==
像[[彗星]]上的[[彗髮]]就是克努森層，因此特別用在彗髮的化學模型中（ComChem model）<ref>{{cite journal|title=First Polymer in Space Identified in Comet Halley|journal=Science|date=1987-08-07|doi=10.1126/science.237.4815.628|url=http://science.sciencemag.org/content/237/4815/628|language=en|volume=237|issue=4815|pages=628–630|issn=0036-8075|accessdate=2018-04-02|author=W. F. Huebner|archive-date=2018-06-04|archive-url=https://web.archive.org/web/20180604184149/http://science.sciencemag.org/content/237/4815/628|dead-url=no}}</ref>。

==參考資料==
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[[Category:流體動力學]]

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