Real-gas behavior for turbomachinery is sometimes empirically accommodated
through the expression W
∙ ig, where W
∙ ig is the ideal-gas mechanical power
and 〈Z〉 is some suitably defined average value of the compressibility factor.
(a) Rationalize this expression.
(b) Devise a turbine example incorporating real-gas behavior via residual properties,
and determine a numerical value of 〈Z〉 for the example.