Evolution of Specific volume of wet saturated steam -thermodynamics :

Specific volume of wet saturated steam (V_wet)

It is volume occupied by unit mass of wet saturated steam corresponding to given pressure of steam generation.

Sp. volume of wet saturated steam can be given by

Vwet  = volume occupied by 'x' kg dry saturated steam + volume occupied by (1 - x) kg. water, here,

x = dryness fraction of the wet saturated steam.

Let v_g = specific volume of dry saturated steam in m³/kg corresponding to the given pressure of wet saturated steam.

v_f   = sp. volume of water in m3/kg corresponding to given pressure of wet saturated steam. Then,

V_wet = x.vg + (1 - x) v_f   m3/kg.

As (1 - x) v_f  is very small compared to x.v_g , it is neglected.

[Average value of v_f  = 0.001 m³/kg upto atmospheric pressure].

Thus,

V_wet = xvg  m³/kg.