| Product(s): |
HAMMER |
| Version(s): |
08.11.XX.XX and 10.00.XX.XX |
| Area: |
Layout and Data Input |
Problem
Why do I need to enter a "nominal head" and "nominal flow" when modeling a pump startup event?
Solution
When modeling a pump startup event by using the "pump start - variable speed/torque" transient pump type, the "nominal head" and "nominal flow" represent the operating point of the pump once it has started up and reached full speed. The reason why this is needed is because HAMMER uses a special 4-quadrant pump curve during the transient simulation (not your pump definition) which has points that are relative to the nominal operating point. So, since the initial head/flow are zero in this case, HAMMER needs you to enter the nominal operating point, so it's able to use the 4-quadrant pump curve. Typically you would simply compute a steady state simulation with the pump on, record the operating point, turn it back off, then use that for the nominal head/flow.
See Also
OpenFlows Product TechNotes And FAQs
Modeling A Pump Start-Up Transient Event In Bentley HAMMER V8i [TN]
Is it possible to model more than one pump starting up at the same time?
Pump Startup occurs too quickly / initial upsurge too severe