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Wet Steam Specific Volume

 

Wet Steam Specific Volume Formula

\( \upsilon_{ws} \;=\; \upsilon_{ds}  \cdot  \zeta  \) 
Symbol English Metric
\( \upsilon_{ws} \)  (Greek symbol upsilon) = Wet Steam Specific Volume  \(ft^3\;/\;lbm\) \(m^3\;/\;kg\) 
\( \upsilon_{ds} \)  (Greek symbol upsilon) = Dry Steam Enthalpy  \(lbf-ft\)  \(J\)
\( \zeta \)  (Greek symbol zeta) = Wet Steam Dryness Fraction  \(dimensionless\) \(dimensionless\)

 Wet steam specific volume is the volume occupied by a unit mass of wet steam.  Wet steam itself is a two-phase mixture consisting of saturated steam (water in its gaseous state) and entrained liquid water droplets.  This condition often arises from heat loss in steam pipes causing some steam to condense, or during the steam generation process where water droplets are carried with the steam.  The specific volume, a fundamental thermodynamic property, is generally defined as the total volume of a substance divided by its total mass.  For wet steam, this property is dependent on its quality (or dryness fraction), which is the proportion by mass of dry steam in the mixture.  Therefore, the specific volume of wet steam is a weighted average of the specific volume of the saturated liquid water and the specific volume of the dry saturated vapor, determined by the dryness fraction.

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