TITLE.PM5

FIRST LAW OF THERMODYNAMICS 197

dharm

/M-therm/Th4-6.pm5

In case the process is steady flow reversible adiabatic, then first law energy equation can be
written as
u 1 + p 1 v 1 + Q = u 2 + p 2 v 2 + W
where v 1 and v 2 are the specific volumes of steam before and after executing the process.
∴ h 1 + 0 = h 2 + W (Q Q = 0)
∴ W = (h 1 – h 2 ) ...(4.78)

2

a

p (^11)
pa
p 2
p
v 2 v 1 v
(a)
(b)