Hello colleges,
I would like to share a model for pipe line i want to make protection from hammer using dipping tube and vacuum breaker to get the -ve pressure below -0.5 bars. Although I tried different volumes and position for the tank and the breaker, still the -ve pressure on the control valve remains out of range.
New folder (2).rarI would be happy for any suggestion/solution for this situation prefer using hydropneumatic dipping tube or/and vacuum breaker as protection devices
If you check the elevations of air valves, they are slightly higher than the reservoir R1, e.g. AV 10, as long as HGL is lower than elevation, you will observe negative pressure as pump is off and tank will eventually drain out since there is no other source of water. See below article to understand more about what could be happening,
Negative pressures occur during a transient simulation no matter what protection is used - OpenFlows | Water Infrastructure Wiki - OpenFlows | Water Infrastructure - Bentley Communities
You may need to consider how long the pumps will be off and size the surge protection device(s) based on that. You may need to consider how long the pumps will be off and size the surge protection device(s) based on that.
So what you could do is estimate how long the pump will be off, and try to restart the pump, because restarting the pump will expel the air out, build positive pressure, which will again have impact on system which you would be interested in. You may need to consider how long the pumps will be off and size the surge protection device(s) based on that.
Modeling a pump startup and shutdown transient event in the same simulation - OpenFlows | Water Infrastructure Wiki - OpenFlows | Water Infrastructure - Bentley Communities
Regards,
Sushma Choure
Bentley Technical Suppport
Answer Verified By: Abdallah Magdy