Since the stagnation temperature at the outlet of impeller is same as that at the outlet of the diffuser, one can also write
in place of
in Eq. (7.6). Typical values of the power input factor lie in the region of 1.035 to 1.04. If we know we will be able to calculate the stagnation pressure rise for a given impeller speed. The variation in stagnation pressure ratio across the impeller with the impeller speed is shown in Figure 7.2. For common materials, is limited to 450 m/s.
Figure 7.3 shows the inducing section of a compressor. The relative velocity
at the eye tip has to be held low otherwise the Mach umber (based on
) given by
will be too high causing shock losses. Mach number
should be in the range of 0.7-0.9. The typical inlet velocity triangles for large and medium or small eye tip diameter are shown in Figure 7.4(a) and (b) respectively.
Figure 7.2 Variation in stagnation pressure ratio with impeller tip speed
Figure 7.3 Inducing section of a centrifugal compressor
in place of
in Eq. (7.6). Typical values of the power input factor lie in the region of 1.035 to 1.04. If we know 
we will be able to calculate the stagnation pressure rise for a given impeller speed. The variation in stagnation pressure ratio across the impeller with the impeller speed is shown in Figure 7.2. For common materials, 
is limited to 450 m/s. 
at the eye tip has to be held low otherwise the Mach umber (based on
) given by
will be too high causing shock losses. Mach number
should be in the range of 0.7-0.9. The typical inlet velocity triangles for large and medium or small eye tip diameter are shown in Figure 7.4(a) and (b) respectively. 
