SECOND LAW OF THERMODYNAMICS
sections in and out. Entropy may also be added to the control volume because of heat transfer
at the boundary of the control volume.
Figure 23 Control Volume for Second Law Analysis
A simple demonstration of the use of this form of system in second law analysis will give the
student a better understanding of its use.
Example 3: Open System Second Law
Steam enters the nozzle of a steam turbine with a velocity of 10 ft/sec at a pressure of
100 psia and temperature of 500°F at the nozzle discharge. The pressure and temperature
are 1 atm at 300°F. What is the increase in entropy for the system if the mass flow rate
is 10,000 lbm/hr?