Questions about pump modeling in HAMMER

Hello Thanasis,

 

Before performing the transient analysis in Hammer, you should perform the hydraulic analysis of the model using either WaterCAD or WaterGEMS.

The initial conditions like pump modeling, tank modeming should be done first in WaterCAD/GEMS before performing the transient analysis.

 

The pump combination curve option is available in WaterCAD, WaterGEMS and SewerCAD but not in Hammer.

Here is technote including detailed information about Pump combination curve.

 

You can enter the pump curves by going to Components>Pump definitions and pump start stop levels can be configured with the help of the controls.

Please see below link to know more about how to set up the controls in model.

http://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/2567.creating-controls-conditions-actions-and-control-sets-tn

Hi Sushma,

Thank you very much for your response. I have one more question. I understood that in Hammer currently there is no way to create a combination curve. So if as you said I create 2 parallel pumps (duty - assist) with their relevant curves, will Hammer calculate the initial conditions if i set up the pump on -off controls based on the combined curve if both the pumps are on?

Hello Thanasis,

Yes Hammer does calculate the initial conditions based on the given pump input data like pump curve, controls etc. results of which are used further for the transient analysis.

HAMMER uses the same exact solver as WaterCAD and WaterGEMS for the initial conditions (steady state or EPS). The provides the starting conditions for the transient simulation.

I see that you mentioned a "combination curve" - if you're referring to modeling a single pump node to represent more than one pump, I would advise against doing this in HAMMER. Although you might have accurate initial conditions, the transient response may be skewed. For a transient simulation, it is important to model things as they are, since modeling artifacts and shortcuts could potentially significantly effect how the transients interact in the network.

The Combination pump curve tool in WaterCAD and WaterGEMS allows for multiple pump curves, efficiency curves, wire-to-water efficiency curves(overall efficiency curve), and system head curves to all be displayed on a single graph. More on that tool here:

Pump Station and Pump Combination Curves

Hi Jesse,
I was referring to the use of 2 different pump elements, (nodes) to Hammer.