The Beale number is a parameter that characterizes the performance of Stirling engines. It is often used to estimate the power output of a Stirling engine design. For engines operating with a high temperature differential, typical values for the Beale number range from (0.11) to (0.15); where a larger number indicates higher performance. The following formula is used: `B_n=W_O/(PVF)`, where:
Wikipedia (https://en.wikipedia.org/wiki/Beale_number)