Dear All,
I have designed a water supply system. In this system there are four pumping stations. (Fixed location). I have assigned my desired flow and head to each pump and demand at every junctions. When I have run my model, It's giving me negative pressure in few junctions in distribution lines where elevations are higher than reservoir's elevation as there are many high and low points in whole system. Please suggest me how to solve this negative pressure. Is this problem related to boundary conditions ?
To add to Scott's response: if these are high points where air valves would be located (with potentially partially-full flow) see the following article about the use of the air valve element to properly account for such cases so that the upstream pump "sees" the high point and knows to add enough head to overcome it: Why do I get a negative pressure at a high point in my system? Shouldn't the pump add enough head to push the water over the hill?
Viewing a profile of the area in question (going back to the boundary condition) may help you better understand what's going on.
Regards,
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.
Thanks a lot Jesse. If I assign air release valve at high point and treat this air valve as junction "False" then it gives me error "disconnected from reservoir or tank". I have uploaded my model as well.