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No outflow from surge tank during turbine load acceptance

ref: https://communities.bentley.com/products/hydraulics___hydrology/f/haestad-hydraulics-and-hydrology-forum/204818/hammer-error-message-for-surge-tank/ 

Hi Jesse,

During the load acceptance case, there is no outflow from the surge tank as shown below. Did I miss anything? I have uploaded my model for review. Thanks in advance.

 2020-10-21 1013 JVP Surge Tank Analysis.wtgpkg.zip

  • Hi Jason,

    Since this is a separate problem, I have split your post to a new thread.

    The first screenshot you provided if from the pipe upstream of the surge tank, where the flow shows the flow going through the pipe. The second screenshot shows the flow upstream of one of the three turbines. 

    To view the flow out of the surge tank from the Time Histories tab of the Transient Results Viewer, you would need to compare the flow graph from the pipe endpoint upstream of, and downstream of the tank. (P-2:ST-1 and P-3:ST-1). Use the Report Points collection in the transient calculation options per this article, to add P-3:ST-1 so that you can do this.

    A better way to view surge tank results is to enter a number in the Report Period field (which I see you did) and look at the Extended Node results in at the bottom of the Transient Analysis Detailed Report as explained in this article.

    The reason why you get very little flow out of the surge tank is because the tank inlet diameter is still set to only 5.8 mm. This severely restricts outflow. Since the adjacent pipes are 5.8 meters in diameter, I assume this was a units problem and the tank inlet diameter should be 5.8 meters. If you make this change, re-run the transient simulation and compare the graphs (or look at the text report), you will see surge tank outflow, and the transient results will be much better.


    Regards,

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

    Answer Verified By: Sushma Choure 

  • Thanks again Jesse, got better results now.