Thermodynamics Directory | Heat Transfer Directory
An h-T diagram exhibits the same features as
on the previous property diagrams. Figure 12 isthe
h-T diagram for pure water. An h-T diagram can be constructed
for any pure substance. Asin
the previous property diagrams, there are regions on the h-T
diagram in which two phasesexist
together. The region between the saturated liquid line and
the saturated vapor linerepresents
the area of two phases existing at the same time. The
vertical distance between thetwo
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 ofvaporization,
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 outsidethe
saturation lines results in a subcooled liquid or superheated
steam.

The quality of the mixture at any point in
the liquid-vapor region can be found using the
samerelationship as shown for the P-h diagram.
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