Determine Interstage Pressure for Multi-stages Centrifugal Compressor

How to determine interstage pressure for multi-stages centrifugal compressor ?

For a n-stages centrifugal compressor system with inlet and outlet pressure of P₀ and P_n, the compression ratio (r) should be about the same in each stage.

r = (P_n/P₀)^(1/n)

P₁ = r.P₀
P₂ = r.P1
P₃ = r.P2
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.
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P_n = r.Pn-1