Thermal Compression + Expansion Index

1. Mar 28, 2008

EngNoob

Could anyone tell me what the compression and expansion is used for in a Thermodynamics situation?

What is the notation for Compression and Expansion in a formula?

I am trying to calculate work done by a heat engine.

Thanks

2. Apr 7, 2008

engware

Hi there:

In general, compression is used to compress the working fluid, increase the pressure -- pressurized the working fluid. Work and/or power input are required to do so. In an ideal case, isentropic compression is used.

In general, expansion is used to expand the working fluid, reduce the pressure -- expand the working fluid. Work and/or power output are generated. In an ideal case, isentropic expansion is used.

Here are two URLs when dealing with compression and expansion.

Theoretical background information on compression and expansion:
http://members.aol.com/engware/components.htm

Online calculators dealing with compression and expansion:
http://members.aol.com/engware/calc4.htm

In order to get the full meaning of compression and expansion with respect to the operation of simple power cyles, here are two more URLs dealing with simple power cycles (Carnot, Brayton, Otto and Diesel).

Theoretical background information on simple power cycles:
http://members.aol.com/engware/cycles.htm

Online calculators dealing with simple power cycles:
http://members.aol.com/engware/calc3.htm

Here are two plots regarding the compression power input and expansion power output.

I do hope that the provided URLs will be useful to you when dealing with theoretical background and doing related basic engineering calculations.

Thanks,

Gordan

Last edited: Apr 7, 2008
3. Apr 11, 2008

EngNoob

Thanks for those urls, they have done the trick, I have read, understood, and now completed, so thanks for all the help, most appreciated...

4. Apr 11, 2008

EngNoob:

No problem.

Thanks,

Gordan