Fluid Mechanics and Thermodynamics of Turbomachinery, 5e

Radial Flow Gas Turbines 277
FIG. 8.14. Calculated performance of 90deg IFR turbine (adapted from Rohlick 1968).
FIG. 8.15. Distribution of losses along envelope of maximum total-to-static efficiency
(adapted from Rohlik 1968).
and has a peak hts of 0.87 at Ws = 0.58rad. An interesting comparison is made by Rohlik
with the experimental results obtained by Kofskey and Wasserbauer (1966) on a single
90deg IFR turbine rotor operated with several nozzle blade row configurations. The
peak value of hts from this experimental investigation also turned out to be 0.87 at a
slightly higher specific speed, Ws = 0.64rad.
The distribution of losses for optimum geometry over the specific speed range is
shown in Figure 8.15. The way the loss distributions change is a result of the chang-