I am modeling a pump shutfdown event in HAMMER. When I compare the results with and without a hydroneumatic tank at the node connected to my tank, I see a nice smooth curve when the tank is active but the maximum pressures are higher than those when the tank is inactive. Does this make sense? can this happen? Here is what I see:
Hello Parsa,
This may depend on the setup of the model and of the hydropneumatic tank. It may be worth reviewing a profile through relevant parts of the model to see the overall impact with and without the tank. Looking at a time history graph at the tank may provide some additional information, like how the tank is draining and filling. If the operation of the tank is in question, adjustments to the tank may be useful to see how the results are impacted.
If that doesn't help, it would be useful to see a copy of the model files.
Regards,
Scott
Thanks, Scott. I just uploaded my model file. I am modeling the flow to a distribution system (with a reservoir element) at this time. The other discharge side goes to injection wells and I am not working on that yet (I have closed the valve to that side). This is for a pump shutdown event after 20 seconds into the simulation. If you look at the temporal variation of pressure at the node to HT, the pressures peak to a higher value in the presence of a HT (compared to the case when there is no tank). The HT helps with the low pressures but I am trying to understand if the high peaks are reasonable or not.
You can see flow in and out of the hydropneumatic tank that seems to correspond with the changes in hydraulic grade. That flow in and out of the tank is going to or coming from the downstream reservoir. I added this as a report point in the transient run to confirm that this is the case. Assuming that the settings in the hydropneumatic tank are accurate, I don't see anything that would lead me to believe that the overall results should not be accurate as well.
Answer Verified By: Parsa Pezeshk