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Turbine parameters in Hammer

While setting the specific speed of the turbine, only three preset values are available in the drop down list. If I want to set a new value of the specific speed, how it can be done?

I have read in the help file that we can define our own curves in the XML library but i am not able to trace the XML library.

Pl. provide the step by step procedure for setting a new specific speed. Also in what way and how much does the specific speed affects the transient results?

  • Hello,

    The best resource for steps on creating a custom turbine curve will be in the HAMMER Help documentation under the topic "Pump and Turbine Characteristics in Bentley HAMMER". At the bottom of the page, there are general instructions on how to go about setting up the custom curve for pumps and turbines in HAMMER. This topic also includes background information on the process and some images of what the finished product will look like. The curves that already are available can also be handy for this. This file is called "QuadrantCurvesPredefined.txt" and can be found in the HAMMER installation folder.

    If you have already created a custom curve, have confirmed that it is set up correctly, but it is not recognized by the program, it may be related to the version of HAMMER you are using. When HAMMER is installed on a 64-bit machine, both the 32-bit and 64-bit versions of the program are included. The QuadrantCurve.txt file you need to edit will depend on the version of the program that you are using. You can find out what version you are using by going to Help > About HAMMER. If you are using the 64-bit version, this will be displayed in the lower left near the build number.

    If you are using the 64-bit version of HAMMER, you will need to edit the text file found at C:\Program Files (x86)\Bentley\HAMMER8\x64\QuadrantCurve.txt. When you do this, the specific speed will be listed. If you edit the 32-bit version of the quadrant curve text file (found at C:\Program Files (x86)\Bentley\HAMMER8), the specific speed will not be listed. This information is documented in the support solution found here: communities.bentley.com/.../11104.custom-quadrant-curve-not-being-recognized.aspx

    For more information on turbines in general, please see the following TechNote:

    communities.bentley.com/.../7139.using-turbines-in-bentley-hammer.aspx

    If this doesn't help, we may need to see the curve you are using or get further steps on what you have done in order to ascertain what is happening. There are two options for sharing your files on Be Communities. If you would like the files to be visible to other members, compress the files into a zip file and upload them as an attachment using the ‘Advanced Reply editor’ before posting. If your data is confidential, you can follow the instructions in the link below to send it to us via Bentley Sharefile. Files uploaded to Sharefile can only be viewed by Bentley.

    communities.bentley.com/.../bentleysecurefilesupload.aspx

    Regards,

    Scott Kampa

    Bentley Technical Support

    Answer Verified By: Scott Kampa 

  • I'd also like to add a few things regarding your question:

    "Also in what way and how much does the specific speed affects the transient results?"

    Typically selecting one of the three available default Specific Speeds is sufficient for transient analysis purposes. Your turbine's specific speed can be estimated using the equation mentioned in the help and in the general turbine modeling technote that Scott linked to. You would then pick the closest of the three default specific speeds.

    If you're not sure if the closest default is sufficient or if you need to look into entering your own custom characteristics curve, a sensitivity analysis may be a good start. Try each of the three specific speeds and see how they effect the transient response with the event being simulated. If they don't have a significant impact, then you may not need to worry about it.

    If you do feel that you need to enter your own specific speed, the guidelines that Scott mentioned can be used, but that information is sometimes difficult to find, since you need a set of curves, one for each position of the wicket gate.

    As for how the specific speed effects the transient results, take a look at the chapter in the help called "Turbine simulation in HAMMER". It acts as a performance curve to calculate the change in head and flow at the turbine based on other changes in the model.


    Regards,

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

    Answer Verified By: Scott Kampa