Air enters a two-stage compressor operating at steady state at 520°R, 14 Ibf/in.2 The overall pressure ratio across the stages is 16 and each stage operates isentropically. Intercooling occurs at constant pressure at the value that minimizes compressor work input, with air exiting the intercooler at 520°R. When the temperature of the air entering each compressor stage is the same, the minimum total compressor work input per unit of mass flowing occurs when the pressure ratio is the same across each stage. Assuming ideal gas behavior, with k = 1.4, determine the work per unit mass of air flowing for the two-stage compressor, in Btu per Ib of air flowing.

Air enters a two-stage compressor operating at steady state at 520°R, 14 Ibf/in.2 The overall pressure ratio across the stages is 16 and each stage operates isentropically. Intercooling occurs at constant pressure at the value that minimizes compressor work input, with air exiting the intercooler at 520°R. When the temperature of the air entering each compressor stage is the same, the minimum total compressor work input per unit of mass flowing occurs when the pressure ratio is the same across each stage. Assuming ideal gas behavior, with k = 1.4, determine the work per unit mass of air flowing for the two-stage compressor, in Btu per Ib of air flowing.