I use the Explicit SWMM solver dynamic wave as a solver in SewerGems to model two pumps in parallel. But I see that the solver doesn't account for losses and uses only the last point of the pump curve. My question is to know if is it possible that the solver takes into account the curve of the pumps as input (taken into account the pressure drops) and is not limited only to the last point of the curve?
I share my model "Farmer.zip" as confidential files. Here, my first concern is with the PMP-1 and PMP-2 pumps. There is no water in the wet wells and the pumps do not output any flow which. This is normal. But a look towards the pipes after the pressure pipe shows that there is a flow equal to the maximum capacity of each pumps. I would like to know how I can fix this problem?
My second problem is with the PMP-4, after the cross-section PJ-4, the pipe has negative flow why? Is there a way to reduce these imperfections?
Your pump PMP-2 is set to "On" but in reality, there is no inflow to the downstream wet-well (PosPom-005) i.e. there is no flow accumulating in the wet-well for the pump to activate and pump flow downstream. From your response to Craig, I think this is expected in your model. Am I right?
However, since the pump status is "On", I think this unaccounted (additional) flow might be considered. Here is a reference article for this;
Unaccounted for flow in SewerGEMS
You can try the options provided in the above article and check the results.
When the pump status is set to "Off" though, these results are not seen i.e. no initial spike in flow in downstream conduit.
For the negative flow at PJ-4, I can suggest using a slightly larger output time-step ("SWMM Output Increment" under Calculation Options). This can give you betterr results.
Hope this helps.
Bentley Technical Support
Answer Verified By: Sushma Choure
Indeed, in my model, I do not expect water in the wet well for this scenario. I would wait to see my results when there will be more water.
Thank you team for help.