Purchase Solution

Rankine Cycle - Net Power, Thermal Efficiency and Heat Transfer

Not what you're looking for?

Ask Custom Question

Water is the working fluid in a vapor power cycle with reheat, superheat and reheat.

Superheated steam enters the first turbine stage at 8 MPa, 480 C and expands to 0.7 MPa. It then is reheated to 480 C before entering the second turbine stage, where it expands to the condenser pressure of 8 KPa. The mass flow rate of steam entering the first turbine stage is 2.63*10^5 Kg/h. Each turbine stage operates with an isentropic efficiency of 58%. The pump operates with an efficiency of 80%.

Determine the net power developed, the cycle thermal efficiency and the rate of heat transfer to the cooling water passing through the condenser.

Purchase this Solution

Solution Summary

This solution is provided in approximately 626 words and attached in a .doc file. It uses step-by-step equations and diagrams to further understand and solve the problem.

Solution Preview


Notations and assumptions:

[ ]* = total features (like p*, T*, h*)
[ ]id = ideal states
[ ]L = referring to liquid state
[ ]V = referring to vapor state
k = adiabatic exponent (for superheated steam k = 1.3)
R = gas constant (for steam R = 461.9 J/kg.K)
= steam mass flow rate [kg/s]
LT , LP = turbine and water pump specific work [kJ/kg]

The diagram of the full cycle is shown in the figure below:

(see attachment)

a) The net power developed can be computed by formula:
(see attachment for equation) ( 1)
The steam mass flow rate is
(see attachment for equation) ( 2)
Now, we need to use the Steam Tables.
State 5: At p = 8 MPa and T = 480 C we find:
(see attachment for equation) ( 3)
We have to check now where is located state 6id (under or above the saturation line)
For s = 6.661 kJ/kg.K, we find on saturation line:
(see attachment for equation) ( 4)
Since p6id = 0.7 MPa = 7 bar < p5s, the state (6id) will be under the saturation line, that is within wet steam area
For p = 0.7 ...

Purchase this Solution

Free BrainMass Quizzes
Architectural History

This quiz is intended to test the basics of History of Architecture- foundation for all architectural courses.