Fluid Mechanics and Thermodynamics of Turbomachinery, 5e

268 Fluid Mechanics, Thermodynamics of Turbomachinery
h/h opt
1.1
1.0
0.9
EXAMPLE 8.4. Given the following data for an IFR turbine
determine the ratio of the relative velocity ratio, w3s/w 2 at the shroud.
Solution. As w3s/cm3 = sec b 3s and w3av/cm3 = sec b3av, then
From eqn. (8.45),
3.0 4.0 4.5 5.0
ZL/D 2
0.8
1.5 2.0 2.5 3.0
r2/r3rms FIG. 8.9. Effects of vane solidity and rotor radius ratio on the efficiency ratio of the
IFR turbine (adapted from Rodgers and Geiser 1987).
The relative velocity ratio will increase progressively from the hub to the shroud.
EXAMPLE 8.5. Using the data and results given in Examples 8.3 and 8.4 together
with the additional information that
6.0