An h-T diagram exhibits the same features as
on the previous property diagrams. Figure 12 is the
h-T diagram for pure water. An h-T diagram can be constructed
for any pure substance. As in
the previous property diagrams, there are regions on the h-T
diagram in which two phase sexist
together. The region between the saturated liquid line and
the saturated vapor line represents
the area of two phases existing at the same time. The
vertical distance between the two
saturation lines represents the latent heat of vaporization.
If pure water existed at point Aon
the saturated liquid line and an amount of heat was added
equal to the latent heat of vaporization,
then the water would change phase from a saturated liquid to
a saturated vapor(point
B), while maintaining a constant temperature. As shown in
Figure 12, operation outside the
saturation lines results in a sub-cooled liquid or superheated
steam.
The quality of the mixture at any point in
the liquid-vapor region can be found using the
same relationship as shown for the P-h diagram.
