11209

Rankine Cycle

In a Rankine cycle (select "Rankine cycle" from drop down menu to view schematic of cycle), high-pressure liquid water (1) enters a boiler where it is heated to saturation temperature (2), vaporized, and superheated (3). The superheated steam is fed to a steam turbine, where it expands and generates mechanical work. The steam exits the turbine at a lower pressure and temperature as either superheated steam or steam at saturation temperature with a quality (4). This steam condenses (5), and a pump compresses the liquid water to high pressure (1). The cycle is shown on a pressure-enthalpy () diagram. Use sliders to vary the inlet pressure to the turbine and to select one of four outlet pressures . Use a slider to vary the turbine efficiency , which is the ratio of work produced by the turbine to the work produced by a reversible turbine between the same inlet and outlet pressures. The pathway for the irreversible turbine () is the thick dashed line on the diagram; the reversible turbine pathway is represented by the thin dotted line. Select "turbine" from the drop-down menu to show the inlet and outlet conditions for the turbine and the work generated.
  • Contributed by: Rachael L. Baumann
  • Additional contributions by: John L. Falconer and Nick Bongiardina
  • (University of Colorado Boulder, Department of Chemical and Biological Engineering)

SNAPSHOTS

  • [Snapshot]
  • [Snapshot]
  • [Snapshot]

DETAILS

The inlet temperature to the turbine, (°C) is set; you can vary the inlet and outlet pressures (MPa). From these conditions the enthalpy (kJ/kg) and entropy (kJ/[kg K]) are obtained from the superheated steam tables.
The superscript denotes reversibility. A reversible steam turbine is isentropic, so , where is the entropy of the steam exiting a reversible turbine.
If at , then the reversible outlet state is superheated.
If at , then the outlet steam is at saturation temperature and consists of liquid and vapor. The quality of the steam is:
,
where is the fraction of vapor, and the superscripts and refer to saturated liquid and saturated vapor.
Depending on the quality of the exiting steam, is obtained from either the saturated steam tables or the superheated steam tables.
If , and is found in the superheated steam tables at and .
If , and .
The change in enthalpy for the reversible turbine is the work for the reversible process.
The efficiency indicates the turbine irreversibility and is the ratio of irreversible work to reversible work. For the irreversible turbine:
.
The screencast video at [1] shows how to use this Demonstration, and the video at [2] explains the cycle.
References
[2] Power Cycle Introduction [Video]. (Mar 15, 2012) www.youtube.com/watch?v=BA77fu3zAbs.
    • Share:

Embed Interactive Demonstration New!

Just copy and paste this snippet of JavaScript code into your website or blog to put the live Demonstration on your site. More details »

Files require Wolfram CDF Player or Mathematica.









 
RELATED RESOURCES
Mathematica »
The #1 tool for creating Demonstrations
and anything technical.
Wolfram|Alpha »
Explore anything with the first
computational knowledge engine.
MathWorld »
The web's most extensive
mathematics resource.
Course Assistant Apps »
An app for every course—
right in the palm of your hand.
Wolfram Blog »
Read our views on math,
science, and technology.
Computable Document Format »
The format that makes Demonstrations
(and any information) easy to share and
interact with.
STEM Initiative »
Programs & resources for
educators, schools & students.
Computerbasedmath.org »
Join the initiative for modernizing
math education.
Step-by-Step Solutions »
Walk through homework problems one step at a time, with hints to help along the way.
Wolfram Problem Generator »
Unlimited random practice problems and answers with built-in step-by-step solutions. Practice online or make a printable study sheet.
Wolfram Language »
Knowledge-based programming for everyone.
Powered by Wolfram Mathematica © 2017 Wolfram Demonstrations Project & Contributors  |  Terms of Use  |  Privacy Policy  |  RSS Give us your feedback
Note: To run this Demonstration you need Mathematica 7+ or the free Mathematica Player 7EX
Download or upgrade to Mathematica Player 7EX
I already have Mathematica Player or Mathematica 7+