Question

Determine whether water at each of the following states is a compressed liquid, a superheated vapor, or a mixture of saturated liquid and vapor.

a. P = 10 MPa, v = 0.003 m3/kg

b. 1 MPa, 190°C

c. 200°C, 0.1 m3/kg

d. 10 kPa, 10°C

Answer 1

a. P = 10 MPa, v = 0.003 m3/kg ,10 MPa

vf = 0.001452; vg = 0.01803 m3/kg,

=> vf < v < vg => so mixture of liquid and vapor.

b. 1 MPa, 190°C : Only one of the two look-ups is needed

P < Psat = 1254.4 kPa so it is superheated vapor

T > Tsat = 179.91°C so it is superheated vapor

c. 200°C, 0.1 m3/kg:

vf = 0.001156 m3/kg ; vg = 0.12736 m3/kg,

=> vf < v < vg => so mixture of liquid and vapor.

d. 10 kPa, 10°C : Only one of the two look-ups is needed

P > Pg = 1.2276 kPa so compressed liquid

T < Tsat = 45.8 °C so compressed liquid

States shown are placed relative to the two-phase region, not to each other.