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How can I simulate "pump stop" with a Periodic Head-Flow?

Hello everyone,

I'm simulating a displacement positive pump with a periodic head-flow and I want to simulate a possible pump stop and seeing the effect downstream. I put in the specifications of Periodic Head-Flow a short time but in the firsts seconds i saw a pressure higher than discharge pressure and this is don't logical.

Thanks 

Regards 

  • The theory behind the equations we solve in HAMMER is based on stopping centrifugal pumps. It may take some research to understand positive displacement pumps.

    What type of pd pump is it (plunger, piston, diaphragm, progressive cavity, lobe). Each of these would decelerate in a different way. The most conservative analysis would be based on an assumption that they stop instantaneously.

    What kind of fluid, velocity, diameter... are you dealing with in this situation?
  • We have certainly seen other users utilize the Periodic Head-flow element to simulate transient effects of a positive displacement pump before, but it sounds like you're describing an "initial surge" where you see a change in flow and/or head at the beginning of the transient simulation when the conditions should still be in steady state. This can be caused by a number of different data entry issues, so a thorough check of the parameters of surrounding elements is a good start. Be sure to animate a profile path in the Transient Results Viewer to understand where the initial surge is coming from.

    For a more specific answer, a copy of the model will be necessary. There are two options for sharing your model on Communities. Either way, be sure to zip your files first. The first option is to attach to your reply on the forum using the Advanced Reply Editor (see link below and to the right of the reply box). If your data is confidential, use the instructions in the link below to send it via Bentley Sharefile. Files uploaded to Sharefile can only be viewed by Bentley.

    communities.bentley.com/.../7079.be-communities-secure-file-upload


    Regards,

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