2008
Equations for the Thermodynamic Properties at the Saturation Line in the Supercooled Water Region
KALOVÁ, Jana and Radim MAREŠBasic information
Original name
Equations for the Thermodynamic Properties at the Saturation Line in the Supercooled Water Region
Name in Czech
Rovnice pro termodynamické vlastnosti na křivce sytých par v oblasti podchlazené vody
Authors
KALOVÁ, Jana and Radim MAREŠ
Edition
Berlin/Germany, Water, Steam, And Aqueous Solutions, Advances in Science and Technology for Power Generation, 5 pp. 2008
Publisher
VDI-Gesellschaft Energie Technik
Other information
Language
English
Type of outcome
Proceedings paper
Field of Study
10301 Atomic, molecular and chemical physics
Country of publisher
Czech Republic
Confidentiality degree
is not subject to a state or trade secret
ISBN
978-3-931384-64-7
Keywords in English
vapour-pressure; triple point; supercooled water; Clapeyron equation; Wagner and Pruß equation; approximation
Tags
International impact, Reviewed
Links
GA101/05/2214, research and development project.
Changed: 8/10/2009 13:46, Mgr. Lenka Bejlková
V originále
Vapour-pressure equations are often used in atmospheric applications. Also properties of water at temperatures below the triple point are needed for calculating saturation pressure in clouds, because clouds are often composed of deeply supercooled water. There are many equations used in meteorology that describe the saturation pressure of H2O also below the triple point. Most of them are based on the Clapeyron equation, because experimental data are not of high quality. Measurements are restricted to temperatures above approximately 235 K, which is the limit of homogenous nucleation. We have compared calculated values with the Wagner and Pruß equation, which also appears to be a very good approximation in the supercooled water range. We have used this equation as a standard equation for vapour pressure and added only a correction term for temperatures from 130 K to 255 K.
In Czech
Tlak syté páry je často používán v atmosférických aplikacích. Výzkum vlastností vody při teplotách pod trojným bodem je nutný pro výpočty tlaku v mracích, které jsou často tvořeny hluboce podchlazenou vodou. K dispozici je mnoho rovnic užívaných meteorology a sloužících k popisu tlaku syté vodní páry také pod trojným bodem. Experimentální data nejsou vysoké kvality, mnohé rovnice jsou založeny na Clausius-Clapeyronově rovnici. Měření jsou limitována hranicí homogenní nukleace. Srovnali jsme vypočítané hodnoty s Wagnerovou-Prussovou rovnicí, která je též doboru aproximací v podchlazené oblasti. Použili jsme tuto rovnici pro tlak syté páry a připojili korekční člen pro teploty od 130 K do 255 K.