Gas work and pressure

[ErkiLeitaru]

Hi, I want to simulate gas work and expansion in cylinder - piston system. The enery nor temperature is not constant and I am in trouble putting gas work into differential equation. Please look at the file (Mathcad 15). I extracted only the question, leaving the diff equs out.

The work done depends on the position of the piston and pressure, which also depends on the position and so on. Quite a mess.

[Fred_Kohlhepp]

One additional problem is that your ideal gas equation is not valid unless the process is adiabatic, and yours isn't.

[ErkiLeitaru]

Hi, why you say it is not valid? As I imagine it, it is valid in every calculation cycle if gas temperature is correctly calculated at each step.

[Fred_Kohlhepp]

Erki Leitaru wrote:

Hi, why you say it is not valid? As I imagine it, it is valid in every calculation cycle if gas temperature is correctly calculated at each step.

I apologise! You're right, I don't know what I was smoking! 😉

[ErkiLeitaru]

Ok, found the answer. The solution is to take a break for a couple of days and relax.

[ValeryOchkov]

May be this will be interesting for you:

http://communities.ptc.com/videos/1680

http://communities.ptc.com/videos/1701

http://communities.ptc.com/videos/1683

and at last this

http://twt.mpei.ac.ru/TTHB/2/tdceng.html