This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

PRV setting can not be maintained?

Hello,

I am facing a problem to set my PRV in the network. I have a network whose topography is a bit sharp and the difference in levels is high. I am fixing PRVs as the pressure exceeded 6 bars. but at some location it seems the PRV just does not produce the required pressure. 

I have attached my model as wMODL.zipell.

regards 

Parents
  • Hello Ahmed,

    Which scenario are you using?

    The only scenario that isn't set to perform a fire flow analysis is the "Peak hourly demand", but when I compute this scenario, there aren't any user notifications and the PRV results are shown below. None of the PRV pressures exceed 6 bars for that steady state scenario.

    It appears you are using version 08.11.06.113?

    Are you using WaterGEMS or WaterCAD?

    What patch set version do you have applied? You can find the date of the applied patch set by going to Help > About WaterGEMS/WaterCAD. The date will appear on the lower-left corner of the about dialog.

     

    Regards,

    Craig Calvin

    Bentley Technical Support

  • Hello Craig,

    I am using waterGems 08.11.06.113 applied patch at 1/27/2016.

    I am computing the fire scenario. and when i try to fix PRV like at J-82 first of all the pipe is seemed to be closed. and the pressure downstream the PRV does not maintain at the pressure value set.
  • It is designing. and this 4 m/s velocity is only at the field of "max pipe velocity" in the fire table results.
    while I am checking the pipes one by one using the fire result browsers and did not give me that much velocity only around 2 m/s !!
  • Ahmed,

    Are you saying that you're selecting the fireflow node in the fireflow results browser that displayed 4 m/s as the max pipe velocity in the fireflow flextable? Do you have the auxiliary results section of the fireflow alternative configured to save results for all elements? (otherwise the results in the model when clicking fireflow nodes in the results browser may not be showing all results).

    Also in the fire flow flextable, check the field "pipe with maximum velocity" along with the total available fireflow. Add that total available fireflow to the fireflow node in question, run a simple steady state and check the velocity in that pipe.


    Regards,

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

  • Hello Jess,
    Yes the auxiliary report option is active. my concern is what i got in the fire node table under "max pipe velocity" is not the same as the fire browser results


    regards
  • Please submit the model for review along with steps to reproduce:

    Sharing Hydraulic Model Files on the Haestad Forum


    Regards,

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

  • I have shared it the file name is MODL.Zip
Reply Children
  • Thanks for sharing the model. The auxiliary results section of the fireflow alternative is not configured to save auxiliary results for your pipes, so results will be "N/A" for all elements when clicking nodes in the fire flow results browser.

    See related article about this: Results show as "N/A" when clicking a node in the Fire Flow Results Browser

    As an example, if I create a selection set of all elements in the model, select it as the Auxiliary Output Selection Set and select "All nodes" for the results type:

    ... then the results will be saved and you will be able to see velocities in pipes when clicking a fireflow node in the fireflow results browser.

    For example in the fireflow flextable, the fire flow node "J-1" shows "Velocity of maximum pipe" as 3.38 m/s and the "Pipe w/ maximum velocity" as P-336. If you click J-1 in the fireflow results browser, open the pipe flextable and sort on the Velocity result field, you will see that the maximum velocity is indeed 3.38 m/s, in a few pipes including P-336:

    Looking at the model plan view, these high velocity pipes are located at the source, where all of the flow is passing through 227 mm pipes that connect to the source reservoir. It looks like these pipes may be too small to handle the desired fire flow along with the other demands in the model.

    Note that the fire flow alternative is not configured to use velocity as a constraint. If 3.38 m/s is not an acceptable velocity, you may want to specify the velocity constraint, so that the available fireflow results show the flow available while not exceeding the velocity constraint (or pressure constraints). This will allow you to see the change in available fireflow as you try upsizing those 227 mm pipes.


    Regards,

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