Hi, I have a site with several wells, a raw water piping system, a water tower, and a potable water piping system. (Don't ask questions about the treatment and filtration of this water.. the answer is not optimal and outside the scope of this question). I believe I've set my elevations correctly, as well as my pipe directions.
I am getting a flow of -340,282,346,638,529,000,000,000,000,000,000,000,000.0 gpm at the pipe between one of the wells and its corresponding pump. I've even tried putting check valves in the pipes but I can't stop it.
Unfortunately I can't post the WTG file publicly due to the nature of the buildings in the network and the information I have on them. Any ideas as to what's happening?
Is this the flow from your well to the pump?
I am assuming you have modeled the well as a tank element (finite volume). You can check the pump curves to determine if the pump is properly setup.
Here is the relevant article for pump selection;
General Pump Selection Process
Also, I think you might have entered the pump curve values in one unit system and then changed the units. This can cause the incorrect flow values to be entered. You can check that too.
Is it possible for you to share a schematic of the setup with key elevations? We can try to recreate your model to check if we get the same result.
You can also share a sample model (removing the confidential data) and upload it securely via this link.
Hope this helps.
Bentley Technical Support
Hi Yashodhan, thanks for the reply!
This flow is going into the well from the pump - backwards from what it should be. I've checked that the pump downstream pipe is set correctly.
I've modeled the wells as reservoirs - infinite volume. For our analysis we're not interested in how much water is in the well.
I believe my pump curves are set up properly; I've included the pump curves in the upload. The model is gigantic, so look for Well #1 (ID 974) and Well #2 (ID 975).
Thanks for your help!
Dear Didier, verify that your discharge pipe is "check valve" or does not find a return of the water in the discharge ...
If you are seeing such unreasonable results, my guess is that there are user notifications returned when computing and validating that would be valuable clues to start with.
It is common for strange results to be returned when there is a "Network Unbalanced" user notification. If you are seeing that, then take a look at the following article for troubleshooting steps.
If there are other user notifications returned, start by troubleshooting the ones with a red icon (errors), then look at ones with a yellow icon (warnings). I recommend searching the wiki database for the user notifications you are seeing. If you can't find a solution, then provide the user notification text and we should be able to elaborate on the cause and solution.
I just noticed that you were able to upload your model files with the confidential method.
The issue is due to variable speed pump batteries being in parallel as suggested by the red user notifications:
"Variable Speed Pump Battery...has inconsistent results. Calculation may be unbalanced. Please ensure pump batteries are not in parallel."
I recommend either using variable speed pumps (VSPs) in parallel, or using a single variable speed pump battery (VSPB).
Answer Verified By: Didier Renault