Fluid Mechanics and Thermodynamics of Turbomachinery, 5e

Determining the velocities and heads needed,
The manometric head is
and the hydraulic efficiency
Performance of centrifugal compressors
Determining the pressure ratio
Consider a centrifugal compressor having zero inlet swirl, compressing a perfect gas.
With the usual notation the energy transfer is
The overall or total-to-total efficiency hc is
Now the overall pressure ratio is
(7.21)
(7.22)
Substituting eqn. (7.21) into eqn. (7.22) and noting that CpT01 = gRT01/(g - 1) =
a 2 01/(g - 1), the pressure ratio becomes
From the velocity triangle at impeller outlet (Figure 7.1)
Centrifugal Pumps, Fans and Compressors 229
(7.23)