Note that the two curves isobars choices are the same as adopted in the examples for the Rankine cy

The adiabatic The vapor pressure of water transformation isobaric steamtable adiabatic expansion of the vapor in the Mollier diagram the isothermal transformation at constant volume of water vapor density: The density of lateral considerations Transformations isochoric and isobaric transformation: considerations on trade The energy of Manson free piston engine - Episode 07
To analyze the process of adiabatic expansion of the steam, instead of 'numerical approach, steamtable you can adopt one type of chart that is based on the use of the Mollier steamtable diagram. This diagram focuses a wealth of information: for this is of some complexity and at first glance many people fail to understand it and using it. To facilitate understanding has been chosen to show the various steps in the construction of a simplified version in which only shows the curves of interest. The Mollier diagram is built up on the HS, that is, the enthalpy is plotted as a function of entropy. Without going into the details of the physical meaning of entropy, steamtable not necessary for the use of the diagram, the reader is sufficient to know that an adiabatic (and more precisely reversible adiabatic) is a transformation type isentropic, ie constant entropy. This means that in the adiabatic HS plane is represented by a linear stretch vertically. Regarding the enthalpy please steamtable refer to what is already written on the understanding that for the contents treated in this post is of secondary importance. Will be taken up and explained extensively how to interpret it at the appropriate time in other writings. In the following values were plotted as a function of the enthalpy entropy relative to the liquid state and the state of saturated steam.
The blue curve shows the trend of the liquid state by 0,1bar for pressures up to the critical pressure, the red curve shows the evolution of the state of saturated steamtable steam from the critical pressure up to a pressure of 0,1bar. These two curves separate two parts of the plan. Above the curves are the points that represent states of superheated steam. steamtable Below the curves is the localized area of coexistence with the liquid phase of saturated steam. Note that the point at 0.1 bar of blue curve the condensed fraction is equal to 100%, that is the only liquid phase. steamtable The condensed fraction is unchanged (ie, it is always equal to 100%) across the length of the blue curve up to the critical point. The critical point is meaningless the distinction between liquid and vapor. steamtable The red curve is related to the state of saturated steam which is absent in the liquid phase: the condensed fraction is equal to 0%. Even if the value of the fraction of vapor condensed in the curve has been shown only in the point where the pressure is equal to 0,1bar it is unchanged (that is always equal to 0%) for the whole extension of the red curve. In the following was added to the curve that describes the transformation that 10bar isobar in part from the liquid steamtable state at a temperature of 179.9 C (temperature of vaporization to 10bar) to get to the state of superheated steam at a pressure of 10bar and the temperature of 550 C.
The curve portion fuchsia color represents the vaporization process that takes place at constant pressure (10 bar) and constant temperature (179.9 C). When the system is in one of the points of this curve are present both the liquid and the saturated vapor. The black lines represent states in condensed fraction constant (the value of the latter is indicated in the vicinity of the start point of the curve). The portion of the curve of light blue color represents the process of overheating isobar 10bar from 179.9 C to 550 C. In the following has been added to the curve that represents the isobaric pressure of 1 bar (light blue curve).
Note that the two curves isobars choices are the same as adopted in the examples for the Rankine cycle of saturated steam and for the Rankine cycle the superheated steam. Assuming that the initial status steamtable of adiabatic expansion is the saturated steam at 10 bar and that the adiabatic expansion takes place up to a pressure of 1 bar, the transformation is represented by the yellow vertical line.
To determine the condensate fraction is evaluated by looking on the black curves what is the value that is closest to the intersection of the vertical yellow line (adiabatic) and the blue light curve (isobar at 1 bar). Click on the picture you can view a higher resolution. It is found that the value of the condensate fraction is close to 13% in perfect agreement with that calculated in the post titled "The adiabatic expansion of saturated steam - Episode 02". The last image the proposal relates to an adiabatic expansion in which