Setting up components of pump station in SewerGEMS

Hello Nishadi,

There is an example of setup of wet well, pump , pressure pipes etc. in the sample models of SewerGEMS.
Please have a look at sample 3 & sample 4 located at C:\Program Files (x86)\Bentley\SewerGEMS8\Samples.

Regards,
Sushma.

Thank you for the reply Sushma. In those two example it does not represent the hydraulic behavior in side the pump station. In my case, what I'm looking for is to way to represent the components of the pump station (Inlet well --> coarse screen chamber--> grit removal section--> ......--> wet well ---> pump---> Force main) in most appropriate way to represent the real condition using sewerGEMS. My first question is whether I can do that using sewerGEMS. If I have no choice I will follow the similar examples.

Regards
Nishadi

Nishadi,

Usually the head losses through those facilities are so small that they can be neglected when you are running a model of the system.

However, if you want to model them explicitly, you can treat the screen chamber as a control structure and you can treat the grit chamber as a conduit with a rectangular/trapezoidal/user defined conduit Section Type.

As a follow up to Tom's reply:

If the headloss through the component can be reasonably simulated with the standard orifice or weir equations, you can select "true" for "Has Start Control Structure?" or "Has Stop Control Structure" in the properties of the conduit, then define the properties of the control structure.

If you can model the component with the standard headloss equation in a pressure pipe, use the "Minor Loss Coefficient" field in the pressure pipe properties.

As a side note, one consideration when using control structures in the numerical solver. If the default Implicit dynamic wave solver has difficulty converging with these control structures in place and you cannot simplify them into a single structure (or neglect them), consider using the GVF Convex solver. (see Conduit Control Structure section of this article). There are other differences to consider (you can read about some of them in this article) but conduit control structure and pressure pipe minor losses tend to be more stable.

Lastly, here is another article with general information about modeling things that may not have an explicit element type.

Thank you..!
Need a nother advice. In this pump station I have two pumps and I want to set the controls according to the wet well level increasing and decreasing scenaros.
I want to model it in implicit numericle solver. But there, it is not allowed to create any controls. Any advice on that? Following is my requirement.

wet well level increasing scenario: pump A start (vfd) and if ww elevation exceed certain level pump B (vfd) starts.
When both pums are in 'on' condition, wet well level will gradualy decrease.
wet well level decreasing scenario: when the wet well level passes a certain low level pump A will be switched off. And the pump B will be swiched off when the ww level passes the specified lowest level.

Thank you..!
Nishadi

Hello Nishadi,

For the Implicit solver, you can setup the on/off conditions for the pump based on the wet-well levels in the properties of the pump.
Meaning based on certain desired levels of the wet-wells you could set up when pump A should turn off and when the pump B should turn on.

If you want to setup the controls using the Controls tab (Components>Controls), you would need to use the GVF-Convex solver , as these controls are not applicable for Implicit and Explicit solvers of SewerGEMS.
Here is the technote about difference between the GVF-Convex solver and the Implicit solver, which will help you in deciding which solver to use.
communities.bentley.com/.../11852.sewercad-gvf-convex-solver-vs-sewergems-implicit-and-explicit-dynamic-solvers

Regards,
Sushma.

Thank you Sushma. I will have a look and try to sort it out.
Regards,
Nishadi

Thank you Sushma. I will have a look and try to sort it out.
Regards,
Nishadi