Problem statement

The problem we will solve is a typical problem solved by a power system engineer trying to analyze the expected performance of a power plant being designed. Here is the problem statement:

Steam is the working fluid in an ideal Rankine cycle. Saturated vapor enters the turbine at 8.0 MPa and saturated liquid exits the condenser at a pressure of 0.008MPa. The net power output of the cycle is 100 MW.

Analysis objectives:

Determine

  1. the thermal efficiency of the cycle,
  2. the back work ratio,
  3. the mass flow rate of the stream, in kg/h,
  4. the rate of heat transfer, Qin', into the working fluid as it passes through the boiler, in MegaWatts, and
  5. the rate of heat transfer rate from the condensing steam as it passes through the condenser, in MegaWatts
Assumptions:
  1. Each component of the cycle is analyzed as a control volume at steady state.
  2. All processes of the working fluid are internally reversible.
  3. The turbine and pump operate adiabatically.
  4. Kinetic and potential energy effects are negligible.
  5. Saturated vapor enters the turbine. Condenstate exits the condenser as saturated liquid.

Given values:

  1. QUALITY of the inlet stream of the turbine = 1.0
  2. PRESSURE of the inlet stream of the turbine = 8,000,000 Pa
  3. PRESSURE of the inlet stream of the boiler = 8,000,000 Pa
  4. QUALITY of the outlet stream of the hot flow side of the condensor = 0.0
  5. PRESSURE of the outlet stream of the hot flow side of the condensor = 8,000 Pa
  6. PRESSURE of the outlet stream of the turbine = 8,000 Pa
  7. NET WORK OUTPUT RATE of the power cycle = 100,000,000