About pumps and turbines

Any referenced datasets can be downloaded from "Module downloads" in the module overview.

In InfoSurge Pro, pump and turbine operation changes can be simulated to predict and prevent potential surge events.

Changes in operating speed for pumps and turbines, changes in wicket gate openings for turbines, and unexpected trips resulting from power loss, can all produce hydraulic transients in a pipe system.

A graph of pressure over time at a hospital, with a jagged line showing large pressure fluctuations that begin to dissipate.

Shock Pressure:

Occurs when pumping operation begins suddenly, as during a startup, and fluid is supplied to a static water column.

When a pump goes through a planned shutdown or power outage, it causes water column separation.

When the water column returns, shock pressure occurs.

Two images side by side; on the left, a cartoon comparing shock pressure in a pipe to a train engine colliding with freight cars, and on the right, an image of utility workers trying to fix a water line break in the middle of a street at night.

Cavitation is possible following pump trips, as the flow reversal of the water column causes the collapse of any vapor cavities that may have formed.

Pump Operation:

A time-dependent change in speed ratios (operating speed/rated speed) may be defined for all types of pumps.

Several formulas and the pump curve used to model pumps during normal operation.

Pumps can also be tripped, and the resulting rundown calculated based on the pump and motor inertia and dynamic characteristics described in the pump file.

A trip can be specified with a ratchet, which prevents reverse rotation.

Pump trip and rachet changes require a pump file, which is selected in the pump surge data.

Pump Operation Changes:

Three types of pump operation changes can be simulated in InfoSurge:

  • Pump speed: Curve designated in speed curve dictates speed of pump during surge analysis.
  • Pump trip: At trip start time, pump runs down according to data specified in pump surge data. Once pump loses power, it may continue to turn, or turbine, or it may be forced to run backwards, or reverse turbine.
  • Pump ratchet: A pump trip where a one-way bearing is installed in pump, allowing it to turbine but not spin backwards. Trip start time is time at which pump trip is initiated.

The Speed/Wicket Gate Change Data dialog box, used to describe the pump/turbine operational changes during transient analysis; and below, in the Curve dialog box, the table and associated graph that define the speed curve.

Turbine Operation Changes:

A time-dependent change in the speed ratio or the wicket gate opening may be defined for turbines.

The Speed/Wicket Gate Change Data dialog box, with Turbine Distance Type selected and the Wicket Gate Setting Curve option now available.

Turbines can also be tripped—resulting rundown is calculated based on turbine inertia and dynamic characteristics described in Suter format.

Three types of turbine and wicket gate operation changes can be simulated in InfoSurge:

  • Turbine speed: Curve designated in speed curve dictates turbine speed during surge analysis.
  • Wicket gate setting: Curve designated in wicket gate setting curve dictates wicket gate opening during surge analysis.
  • Turbine trip: At trip start time, turbine runs down according to data specified in pump/turbine surge data.