As the former simple performance prediction methods for the Stirling engines, Beale number, B_N, or West number, W_N is used.

P_m: Mean pressure (Pa)
V_SE: Swept volume of expansion space (m³)
n: Engine speed (rps)
T_E: Gas temperature of expansion space (K)
T_C: Gas temperature of compression space (K)

In the case of the high temperature difference Stirling engines, a standard value of Beal number is 0.15.
A standard value of West number is from 0.25 to 0.35.
The output power can be calculated approximately, when these numbers are used. But, it is necessary that the engine speed when the engine gets the maximum output power is supposed.

In the case of the simple performance prediction method which is proposed on my web page, the output power and the engine speed can be predicted easily. And effects of the kind of the working gas is estimated when the non-dimentional engine specification is introduced.

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