UMLAZI KWAZULU-NATAL
P.O. Box 1263 Jacobs 4026 Durban Tell: 031 907 7111 Fax: 031 907 2892
THERMODYNAMICS APPLIED III: TUTORIAL #3
VAPOUR POWER CYCLE
1.
# Location pressure Quality/temp. velocity
1 Inlet to turbine 6 MPa (60 bar) 380 °C -
2 Exit from turbine or inlet to condenser 10 kPa (0.1 bar) 0.9 200 m/s
3 Exit from condenser or inlet to pump 9 kPa (0.09 bar) Saturated liquid -
4 Exit from pump or inlet to boiler 7 MPa (70 bar) - -
5 Exit from boiler 6.5 MPa (65 bar) 400 °C -
Note: The rate of steam flow is 1000 kg/hr.
Calculate:
a) The power output of the turbine,
b) Heat transfer per hour in the condenser and reboiler separately
c) The mass of cooling water circulated per hour. Choose the inlet temperature of cooling water
of 20 °C and 30 °C at the exit from the condenser.
d) The diameter of the pipe connecting the turbine and condenser.
2. In a steam power cycle, the steam supply is at 15 bar and dry and saturated. The condenser pressure
is 0.4 bar. Calculate the Carnot and Rankine efficiencies of the cycle. Neglect pump work.
3. In a steam turbine steam at 20 bar, 360°C is expanded to 0.08 bar. It then enters a condenser, where
it is condensed to saturated liquid water. The pump feeds back the water into the boiler. Assume
ideal processes, find per kg of steam the net work and the cycle efficiency.
4. A Rankine cycle operates between pressures of 80 bar and 0.1 bar. The maximum cycle temperature
is 600°C. If the steam turbine and condensate pump efficiencies are 0.9 and 0.8 respectively,
calculate the specific work and thermal efficiency. Relevant steam table extract is given below.
P.O. Box 1263 Jacobs 4026 Durban Tell: 031 907 7111 Fax: 031 907 2892
THERMODYNAMICS APPLIED III: TUTORIAL #3
VAPOUR POWER CYCLE
1.
# Location pressure Quality/temp. velocity
1 Inlet to turbine 6 MPa (60 bar) 380 °C -
2 Exit from turbine or inlet to condenser 10 kPa (0.1 bar) 0.9 200 m/s
3 Exit from condenser or inlet to pump 9 kPa (0.09 bar) Saturated liquid -
4 Exit from pump or inlet to boiler 7 MPa (70 bar) - -
5 Exit from boiler 6.5 MPa (65 bar) 400 °C -
Note: The rate of steam flow is 1000 kg/hr.
Calculate:
a) The power output of the turbine,
b) Heat transfer per hour in the condenser and reboiler separately
c) The mass of cooling water circulated per hour. Choose the inlet temperature of cooling water
of 20 °C and 30 °C at the exit from the condenser.
d) The diameter of the pipe connecting the turbine and condenser.
2. In a steam power cycle, the steam supply is at 15 bar and dry and saturated. The condenser pressure
is 0.4 bar. Calculate the Carnot and Rankine efficiencies of the cycle. Neglect pump work.
3. In a steam turbine steam at 20 bar, 360°C is expanded to 0.08 bar. It then enters a condenser, where
it is condensed to saturated liquid water. The pump feeds back the water into the boiler. Assume
ideal processes, find per kg of steam the net work and the cycle efficiency.
4. A Rankine cycle operates between pressures of 80 bar and 0.1 bar. The maximum cycle temperature
is 600°C. If the steam turbine and condensate pump efficiencies are 0.9 and 0.8 respectively,
calculate the specific work and thermal efficiency. Relevant steam table extract is given below.
