Page 288 - Centrifugal Pumps Design and Application

Hydraulic Power Recovery Turbines 25?

Figure 14-6. Rework of pump impeller for operation as an HPRT runner,

Trimming the runner (impeller) diameter, as is done for pumps, to shift
the performance characteristics is not normally done for hydraulic tur-
bines. The turbine runner diameter is selected for optimum running
clearance.
The inlet ends of the turbine runner vanes are ground to a bullet-nose
shape and the inlet edges of the runner shrouds are rounded slightly to
preclude excessive turbulence for efficiency considerations (Figure 14-
6). But before operating a pump as an HPRT at the same speed, one has
to remember the change in performance characteristics. A comparison is
shown in Figure 14-7.