User notification message id 41891

I believe error 41891 is "Pressures below the lowest physically possible" (please confirm). If so, this message is telling you that the pressure somewhere in your network is not only below zero, but below the vapor pressure limit and therefore the results are not valid. Please see the following article for help on troubleshooting negative pressures: Troubleshooting negative pressures at pumps, junctions, & other node elements

If this does not help, please provide the complete set of model files as Scott mentioned, plus details on the message you are seeing and any other specific steps to reproduce.

User notification is 41891 "Base" "Calculation Options" "20" "Base Calculation Options" 0.000 "Pressures below the lowest physically possible pressure in system at one or more time steps. Set up Alerts for details." Pressure Engine

I have a new link, I hope with what is necessary for your help. Thank you

www.transfernow.net/.../20230118blgGabNd

Hello Humberto,

I would recommend reviewing the link Jesse provided for information on this issue. However, I believe that the issue may be related to the pipe diameters. The diameters of all pipes in the model is only 29.4 mm. This can lead to a large headloss in pipes with significant flow. For instance, pipe RED AP (Polyline)-29 has over 50 meters of headloss there alone. This will add up as you move downstream, leading to pressures well below zero. 

Based on this, I would make sure that your pipe diameters are accurate. 

Regards,

Scott

I was looking at your model at the same time and I concur with Scott - the trunk pipes in particular (between "RESERVORIO EXISTENTE" and J-79) are too small for the flow demanded. If you take a look at a profile this becomes more clear:

This is a profile between "RESERVORIO EXISTENTE" and J-101.

If I increase the trunk main pipe diameters to 40 mm for example, the headloss is much less and the negative pressure problem no longer occurs:

I was able to solve the problem. thank you very much for your help

I was able to solve the problem. thank you very much for your help