Dear All,
In Hammer simulation report a triple action air valve allows air to enter to the system to prevent vacuum.
The above mentioned table captured from transient report is illustrating the air volume entered to the pipes.
What is the current volume? Is it the amount of air remains in pipes after transient? and How to release it?
thanks
Hello Mohamed,
Basically these results are pointing out that there is air pocket formation at multiple points along the pipe P-661. I am assuming you are using "Extended CAV" method for tracking air / vapor volume?
Did you try graphing the air volume at this point? Do you see the air volume at the end of the simulation (the time period for transient analysis)?
If possible can you share a snapshot of this graph?
Considering the large volume of air pockets generating in your pipeline, here is an article that might be helpful for you;
Modeling large amounts of vapor or air volume
Hope this helps.
Regards,
Yashodhan Joshi
Hello Yashodhan,
This is the graph.
But i still have the sane question about the previous table:
The "curr vol" in the "list of sorted vapour and air pockets" section of the transient analysis output log shows the air or vapor pocket volume at the end of the transient simulation (last timestep). A positive value here indicates that the system may not have reached a true steady state condition at the end of the transient simulation (since there is still air or vapor left in the system). To see all the air release and the system reach a final steady state, you may need to extend the duration. This is done in the transient calculation options.
Or, if this is for an emergency pump shutdown transient event, the air pocket may not be able to expel until after you turn the pump back on by modeling a shutdown + startup in the same scenario.
I have added this information to the "Reporting" section of the Air valve modeling reference article. See Reporting > Transient Analysis Output Log.
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.
Answer Verified By: Expert