Page 277 - Centrifugal Pumps Design and Application

14

Hydraulic

Power

Recovery

Turbines

by Roif Lueneburg and
Richard M. Nelson
Bingham-Willamette, Ltd.

The potential for power recovery from high-pressure liquid-streams
exists any time a liquid flows from a higher pressure to a lower pressure
in such a manner that throttling occurs. As in pumping, this throttling can
exhibit a hydraulic horsepower (HHP) and a brake horsepower (BHP),
except that in throttling, these horsepowers are available rather than con-
sumed. Hydraulic power recovery turbines (HPRT's) are used instead of
throttling valves to recover liquid power.
The two main types of HPRT's are:
1. Reaction—Reverse running pumps and turbomachines in single-
and multi-stage configurations with radial flow, (Francis), mixed
flow, and axial flow (Kaplan) type runners. They come with fixed
and variable guide vanes. The axial flow Kaplan propeller has ad-
justable runner blades.
2. Impulse—Most prominent is the Pelton wheel, usually specified for
relatively high differential pressures and low to medium liquid
flows.
This chapter will discuss reaction-type HPRT's; namely, the reverse-run-
ning pump (Figure 14-1) and machines specifically designed to run as
HPRT's.
Basically all centrifugal pumps, from low to high specific speed and
whether single- or multi-stage, radially or axially split, and in horizontal
or vertical installations, can be operated in reverse and used as HPRT's,
The discharge nozzle of the pump becomes the inlet of the turbine; the
suction nozzle or bell of the pump becomes the outlet of the turbine, and
246