Page 64 - DJJ20063- Thermodynamics 1

DJJ20063- Thermodynamics 1

❑ At point B, if heating continues, water will change gradually into steam until point C

and the steam becomes dry saturated. Thus we have

area BCHFB = latent heat
= hfg at pressure P

= hC - hB

❑ At point C, the enthalpy is given by
hC = area ABFOA + area BCHFB

= hg at pressure P

❑ For wet steam at point E,

hE = hB + xEhfg
i.e hE = area ABEGOA

❑ When dry saturated steam is further heated, it becomes superheated. The heat

added from C to D at constant pressure P, is given by
Q = hD – hC

= area CDJHC

❑ Then the enthalpy at D is
hD = hC + area CDJHC

= area ABCDJOA

2.4 Relate the ideal gas model to pure substances

2.4.1 Define perfect or ideal gas in terms of the molecular model. Definition Of

Perfect Gases

Did you know, one important type of fluid that has many applications in thermodynamics
is the type in which the working temperature of the fluid remains well above the critical

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