Hi guys,
How is it possible that the characteristics of the hydropneumatic tank modeled on the pressure side of the pump have an influence on the pressure value in the node on the suction side of the pump during transient?
More precisely, in the first scenario, I defined the diameter of the pipe (branch) from the main pipeline to the hydropneumatic tank with DN 250. In comparison, I also observed the condition on the suction side of the pump because in this case a negative pressure of approx. -0.8 bar appears in the node on the suction side.
In the second scenario, I reduced the profile of that same branch from DN 250 to DN 150 and in that case the situation on the suction side improved drastically (the negative pressure dropped to approx. -0.2 bar).
Is this realistic since the activity of hydropneumatic tank on the pressure side of the pump (when the pump is shuted down after time delay) does not, as a rule, affect the suction side? Or does it?
Is it maybe possible that this is an error in the results due to the very small length of the pipe on the suction side (5 m from water chamber to pump), since every time I change the time step interval in the settings, the value of the negative pressure in the observed node on the suction side also changes in the final result?
P.S. Unfortunately, I am not trying to reduce that interval to less than 0.001 seconds, because in that case the calculation of the results takes a very long time.
Thanks in advance for Your help!
Regards!