Determining the Specific Volume of Subcooled Water

Ch 2, Lesson C, Page 13 - Determining the Specific Volume of Subcooled Water

• Suppose you need to know the specific volume of water at 200oC and 5 MPa.
• First, you need to decide the state of the water.  The place to start is by finding Tsat at 5 MPa.
• The subcooled water table shown here indicates that Tsat is 263.94oC at 5 MPa.  Keep in mind that 5 MPa is the same as 5000 kPa, 
• OK, since the actual temperature of the water is LESS than Tsat, we can conclude that the water is a subcooled liquid.
• Therefore, we need to look in a subcooled water table at a pressure of 5 MPa to find properties such as Vhat.
• The subcooled water table for 5 MPa is shown here and, lucky for us, there is a row for a temperature of 200oC.
• So, we can simply pick the specific volume straight from the table.
• The specific volume of water at 5 MPa and 200oC is 0.011531 m3/kg or 11.531 L/kg.
• What if we wanted to know the specific volume of water at 5 MPa and 174oC ?
• I hope you already know the answer.  We have to linearly interpolate on the subcooled water table.
• This works in exactly the same way that interpolation works in the saturation tables.