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Main control valve & min re-circulation control valve operation with time delay

Dear Bentley team,

I have a following queries on Hammer/WaterGEMS,

  1. I have a pumping system with main control valve on discharge line & one more control valve on minimum re-circulation line. I wanted to know that whether I can do simulation when control valve on main discharge line is closing at the same time I need to open control valve on minimum re-circulation line, I can say both valves should operate with a time delay. Is it possible to do this case using Hammer.

 

  1. I need to mention pressure as a input on destination point, where can I mention pressure as a input as fluid vapour pressure is higher than the atmospheric pressure , hence I cannot use either reservoir option or a junction option to allocate the demand. If allocate demand for the junction since initially control valve is in closed condition hence simulation is showing error as initial pressure is less than the vapour pressure. 

Request you to send  reply to another mail ID as well: ramanjaneyulu.ambati@qdcqatar.net

Thank you

Parents
  • I have a pumping system with main control valve on discharge line & one more control valve on minimum re-circulation line. I wanted to know that whether I can do simulation when control valve on main discharge line is closing at the same time I need to open control valve on minimum re-circulation line, I can say both valves should operate with a time delay. Is it possible to do this case using Hammer.

    Yes, you can specify different Operating Rules (closure patterns) on valves for a transient simulation in HAMMER. Use the TCV element and read more in this article: Modeling Reference - Valve Closure

    I need to mention pressure as a input on destination point, where can I mention pressure as a input as fluid vapour pressure is higher than the atmospheric pressure , hence I cannot use either reservoir option or a junction option to allocate the demand. If allocate demand for the junction since initially control valve is in closed condition hence simulation is showing error as initial pressure is less than the vapour pressure. 

    If you need to model a valve that is initially closed but when it opens, water leaves a junction (as a demand), try modeling it as a Discharge To Atmosphere. This is essentially a pressure dependent demand so the outflow will be zero if the pressure is zero, and the outflow will be positive as the pressure rises. If you simply want to assume a constant pressure at the downstream end of the system, convert the pressure to HGL and enter that as the elevation of a reservoir element (and enter the "inlet/outlet invert" elevation as the actual elevation of the discharge point. If this does not help, please explain in a bit more detail what the discharge point represents and what you need to model.

    Request you to send  reply to another mail ID as well: ramanjaneyulu.ambati@qdcqatar.net

    Replies (like this) to a forum thread will generate an email alert for the original poster. If you wish to share the information with someone else, you can forward the email or ask the other person to sign in, view your post and click the "turn reply notifications on" option (which may be seen within the "more" link under your initial post).


    Regards,

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

Reply
  • I have a pumping system with main control valve on discharge line & one more control valve on minimum re-circulation line. I wanted to know that whether I can do simulation when control valve on main discharge line is closing at the same time I need to open control valve on minimum re-circulation line, I can say both valves should operate with a time delay. Is it possible to do this case using Hammer.

    Yes, you can specify different Operating Rules (closure patterns) on valves for a transient simulation in HAMMER. Use the TCV element and read more in this article: Modeling Reference - Valve Closure

    I need to mention pressure as a input on destination point, where can I mention pressure as a input as fluid vapour pressure is higher than the atmospheric pressure , hence I cannot use either reservoir option or a junction option to allocate the demand. If allocate demand for the junction since initially control valve is in closed condition hence simulation is showing error as initial pressure is less than the vapour pressure. 

    If you need to model a valve that is initially closed but when it opens, water leaves a junction (as a demand), try modeling it as a Discharge To Atmosphere. This is essentially a pressure dependent demand so the outflow will be zero if the pressure is zero, and the outflow will be positive as the pressure rises. If you simply want to assume a constant pressure at the downstream end of the system, convert the pressure to HGL and enter that as the elevation of a reservoir element (and enter the "inlet/outlet invert" elevation as the actual elevation of the discharge point. If this does not help, please explain in a bit more detail what the discharge point represents and what you need to model.

    Request you to send  reply to another mail ID as well: ramanjaneyulu.ambati@qdcqatar.net

    Replies (like this) to a forum thread will generate an email alert for the original poster. If you wish to share the information with someone else, you can forward the email or ask the other person to sign in, view your post and click the "turn reply notifications on" option (which may be seen within the "more" link under your initial post).


    Regards,

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

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