Stirlingengineforum.com

Hi,

I am creating a beta Stirling engine and was wondering if there was a good calculation for working out the Displacer and Piston diameter?

Thanks!

So I have found some calculations and done more reading. But I'm still slightly confused. Due to my design being a rhombic drive the piston and displacer stroke are the same length.

Using some rhombic drive calculations I have ended up with a stroke of 0.24m (for the example I'm currently trying) and if I use the 1:1 stroke: bore ratio the bore is also 0.24m.

How can I calculate the diameter of the displacer from these? Currently I have set it to 0.239m which then gives me a displacer length of 0.717m (using length= diameter X3 rule).

when I calculate the swept volume of the displacer I get 0.011m3, which means I get a swept piston volume of 0.008m3 (using 1.5:1 ratio).

This gives me a piston diameter of 0.199m, which seems too small and would lead to a lot of air leakage.

Are these calculations correct? Should my piston diameter (for this example) be this small in comparison to the cylinder bore and how to I stop the air leakage in this case?