Effect of humidity on the thermodynamic behaviour of atmospheric air

Kouremenos, DA; Kakatsios, XK; Krikkis, RN

dc.contributor.author	Kouremenos, DA	en
dc.contributor.author	Kakatsios, XK	en
dc.contributor.author	Krikkis, RN	en
dc.date.accessioned	2014-03-01T01:48:32Z
dc.date.available	2014-03-01T01:48:32Z
dc.date.issued	1999	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/25515
dc.relation.uri	http://www.scopus.com/inward/record.url?eid=2-s2.0-0033300753&partnerID=40&md5=ab3e09b4c3f6df47139b08f5baa662e8	en
dc.subject.other	Atmospheric density	en
dc.subject.other	Atmospheric humidity	en
dc.subject.other	Earth atmosphere	en
dc.subject.other	Pressure effects	en
dc.subject.other	Specific heat	en
dc.subject.other	Thermal effects	en
dc.subject.other	Atmospheric air	en
dc.subject.other	Mach number	en
dc.subject.other	Vapour liquid equilibrium	en
dc.subject.other	Thermodynamics	en
dc.title	Effect of humidity on the thermodynamic behaviour of atmospheric air	en
heal.type	journalArticle	en
heal.publicationDate	1999	en
heal.abstract	The present work considers the thermodynamic behaviour of moist air as a function of the state variables temperature, density and humidity ratio. Moist air is treated as an ideal mixture which is composed of two real gases, air and steam. The state functions of the mixture are expressed using the corresponding explicit relations of the two species from which the three isentropic exponents describing the real gas isentropic change are calculated. Saturated conditions are determined by solving the Vapour Liquid Equilibrium problem for real water. Numerical results show the effect of humidity as well as the effect of pressure on the thermodynamic behaviour of atmospheric air (such as the three isentropic exponents kpρ,kTp,kTρ, the classical isentropic exponent k and the velocity of sound) for a wide range of temperatures and pressures. Furthermore the isentropic change is approximated by explicit relations having mathematical forms similar to those of the ideal gas but with different constants and exponents. The obtained accuracy is remarkable, being better than 0.32%. In this way the isentropic change, of moist air can be computed by simple explicit relations having as independent variable the Mach number and the humidity ratio. The effects of humidity are examined on certain cases of practical interest such as the critical state (M = 1), the impulse function and the mass flow rate.	en
heal.publisher	ASME, Fairfield, NJ, United States	en
heal.journalName	American Society of Mechanical Engineers, Advanced Energy Systems Division (Publication) AES	en
dc.identifier.volume	39	en
dc.identifier.spage	275	en
dc.identifier.epage	284	en