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Modeling throttle valve

Hello There

I want to model a throttle control valve to analyze losses in the pipes when I stop the flow in a part of my network

my question is about modeling the throttle control valve, is that when I try to put a TCV with the initial setting (closed) on a pipe to stop the flow to a certain junction I still get a flow in the pipe and the pressure in the junction become (zero) 

so why does that happens and why do I still get a flow in the pipes?

that doesn't help me to study losses in energy when flow decrease 

I attached 2 images to get a better understanding 

  • Hi Mohamad,

    The numerical solver in WaterCAD and WaterGEMS (steady state and EPS) is demand-driven so if you enter a fixed demand at a junction, it will solve the rest of the network under the assumption that the specific demand must be supplied. So, if you close off a demand from a water source, it will still force the demand through the closed pipe or valve since those two assumptions are conflicting. Meaning, you are saying that a certain flow must leave the system yet that demand is close odd.

    If this is indeed your situation (there is no other path around the closed valve to feed downstream demands), you should see a user notification "disconnected demands detected" to inform you about this condition. If you would like the outflow (demand) to decrease as the pressure decreases (and become zero when fully closed off), you would need to use pressure dependent demands

    See more in this related article: Disconnected Demand Nodes user notification when computing model

    You may also want to consider the Criticality feature.


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

    Answer Verified By: mohamad joun