|MadSci Network: Physics|
First, a few definitions: - "A process that takes place in such a way that no heat flows into or out of the system is called an adiabatic process." (P. 564, Halliday and Resnick, Physics, 1966) - "A reversible process of special importance is the reversible adiabatic process ... the entropy of a control mass undergoing a reversible adiabatic process will not change; such a process of constant entropy is called an isentropic process." (P. 185, Reynolds and Perkins, Engineering Thermodynamics, 1970) - "The Carnot cycle is an ideal power cycle that is impractical to implement. However, its work output sets the maximum attainable from any heat engine ..." (P. 25-8, Michael R. Lindeburg, Engineer-in-Training Reference Manual, 8th Edition, 1992) - Processes that occur at constant temperature are isothermal. The Carnot cycle is frequently illustrated by a pressure vs. volume, temperature vs. entropy, or enthalpy vs. entropy curve showing the path followed by a Carnot cycle in transitioning between four states. Two of the transitions are isothermal (isothermal expansion of saturated liquid to saturated vapor and isothermal compression of vapor), and two of the transitions are isentropic (reversible adiabatic processes) (an isentropic expansion of vapor and an isentropic compression). To put the four processes in context, and assuming a, b, c, and d are different states, the processes are - a to b: isothermal expansion of saturated liquid to saturated vapor - b to c: isentropic expansion of vapor - c to d: isothermal compression of vapor - d to a: isentropic compression Of course, the above would make a lot more sense if accompanied by an illustration. On the web I found the following site with an applet that is at least intriquing http://www.phy.ntnu.edu.tw/java/carnot/carnot.html and the following website with illustrations I thought were better matched to the above http://www.taftan.com/thermodynamics/CARNOT.HTM Hope this helps. Thanks for your question. sid
Try the links in the MadSci Library for more information on Physics.