I am working on Design of a Stirling engine. Thisis an external combustion engine capable of converting heat energy to mechanical work. The working fluid in the engine is oscillatory and hence is in an unsteady state all the the time. Could anyone advise me on the best CFD package that can be used to solve unsteady state fluid flow (here the fluid is air or nitrogen).

kind regards.

Hi,

I am not sure, if you can or should use a CFD-Code for your study. The reason is, as you know, a Stirling engine has a lot of different components, which define the overall performance very much.

You have to be aware of eg.:

- heat transfer in different forms such as the storage and release in the regenerator.

- complex moving geometry, made by the up and down movement of the pistons. I was told how much trouble people already have to model the piston movement in a normal internal combustion engine.

- different kinds or turbulent effects.

- and so on.

I know that people had already a good succes to model internal combustion engines just by coupling simple models for every efect in a computer code. Then you maybe use CFD to study and optimize just one component of the Stirling engine.

Never the less, when I sudied combustion engine I found Stirling engine very nice, and it would be nice if they were be used more widly.

Ciao Heinz

[zdeth]

Rab,

Were you ever successful in modeling a Stirling engine with a commercial CFD package? I"m trying to model a Pulse tube refrigerator which has many similar components and having trouble finding an appropriate way to capture the heat exchangers..

Thanks,