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Geoff Rathbun April 6, 1999 03:31

Engine simulation (seeking help with method to use)

I am wanting to model the thermodynamics of a Stirling engine. This can give quite accurate results by just doing a single dimensional simulation in time. There is no need to do a 3-D analysis. I am wondering how to approach the problem. It seems that CFD technology would work well as the simulation needs to account for:

1. fluid compressibility 2. variable heat exchange with walls 3. flow friction 4. time

These can all be adequately modelled using a single axis approach. Can anyone help me with finding an appropriate theory and code to do this job?

thanks in advance .....Geoff Rathbun (New Zealand)

andy April 6, 1999 05:53

Re: Engine simulation (seeking help with method to use)
If I understand what you wish to do correctly (slightly confused by "single axis approach"), you probably want to look at "filling and emptying" methods rather than "CFD" - it is hard to do something sensible with the vector momentum equation unless the flow is predominantly in an "axial" direction. There is a lot of literature on the subject (mainly from the 70s and 80s) with a wide range of supporting empirical formulae for parts of the engine like ports and valves.

Glenn Horrocks April 6, 1999 18:17

Re: Engine simulation (seeking help with method to use)
Hi Geoff and Andy,

What you are asking sounds a little like some work I did a few years back. Here's a reference I found very useful in my work:

"The thermodynamics and gas dynamics of internal-combustion engines" by Rowland S. Benson ; Edited by J.H. Horlock and D.E. Winterbone (1982)

It's a 2 volume book. The first volume looks at the Method of Characteristics (and has an example code), and the second volume looks at more advanced topics such as the "Filling and Emptying" method.

Hope it helps, Glenn

Tom Wanat April 7, 1999 23:12

Re: Engine simulation (seeking help with method to use)
I work for a company, Gamma Technologies, that makes a commercial engine simulation code, which is a one-dimensional code. Check out our website at

Anil Shenoy April 13, 1999 14:19

Re: Engine simulation (seeking help with method to use)
Hi Geoff,

Please check out the following book:


I think it has the information you need.


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