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Thread: Water quality chlorine set up

  1. #1
    Member
    Join Date
    Dec 2016
    Posts
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    Water quality chlorine set up

    I ahve some doubts when simulating water quality

    *How do I define if I want to use first order decay or second order decay?

    *When simulating water quality chlorine, how do I enter the concentration source? I was trying 2 options
    1. In Tools -> Quality source -> node water quality source -> enter a base line concentration
    2. The same as one, plus a negative flow to show the inclussion of water
    Both methods provide numerical results, but which one is the appropriate method?

    *Are there any suggested values for diffusivity ratio?

    *What is the limiting potential (when simulating temperature)?

    Thank you

  2. #2
    Forum Moderator

    Innovyze Employee



    Innovyze Employee



    Join Date
    May 2015
    Posts
    417
    Vladimir,

    Running a full chlorine analysis is a higher endmodeling task.
    Make sure you take time to read the InfoWater User guidepages 4-29 through 4-41 to best understand how any water quality analysisworks. You can find the InfoWater User Guide here:
    In the Start->Programs -> Innovyze-> InfoWater menuopen the InfoWater User Guide
    Or you can browse to this directory: C:\ProgramFiles(x86)\InfoWater\Help\InfoWater Users Guide.pdf (or Water.pdf)


    Your Question:*How do I define if I want to use first order decay or second order decay?
    Innovyze Response: These are specified in the Simulation options Water Quality Tab in the image shown below. You can define different reaction order coefficients for the Global pipe Bulk Reaction Order, Global Pipe Wall Reaction Order, Global Tank Reaction Order, but only the Global Bulk Reaction Order can be more than zero or 1 for the reaction order. Wall and tank decay reaction orders must be zero or 1st order

    Simulation Options - Quality Tab for Chemical/ Temp analysis - Reaction Order Assignment
    (click if need larger image)
    Simulaiton Options - WQ Constituent Reaction Order.jpg
    Your Question:*When simulating water quality chlorine, how do I enter the concentration source?
    Innovyze Response:
    To specify a continual water quality source at a reservoir one shouldboth specify an Initial Water Quality for the Reservoir as well as assign aquality source in the “hammer menu” of the model explorer with that reservoiras the active element. Specifying a concentration Type and a baselineconcentration will maintain that concentration for all water leaving thereservoir but will not specify the initial Water Quality so specify both to seethe desired concentration over the entire analysis period. If desired you can also specify a pattern tovary the quality over time. If theconcentration is constant leave the pattern field blank. Generally you define WQ sources on Model Reservoirs as these are the true water "sources" in your model. It is much preferred to use a reservoir and a device to control water supply than using a negative demand when doing a chlorine analysis as quality sources on junctions can act unusual. The reservoir method will always work as expected.

    Defining a quality source for a reservoir
    (click if need larger image)
    Defining a quality source.png

    Your Question: *Are there any suggested values for diffusivity ratio??
    Innovyze Response:
    Please review the User Guide pages 4-29 through 4-41 to find guidance on Diffusivity values.

    From the help file:

    • Diffusivity (ratio) - For chemical trace the diffusivity is the ratio of the diffusivity of that chemical to the default diffusivity value; for temperature modeling, the diffusivity ratio is the user water thermal diffusivity to the default water thermal diffusivity.

    For Water Quality Diffusivity:

    • The default value is 1.3*10e-8 ft2/sec, if no value is given
    • If the given Diffusivity term is > 1.0e-4, it is used as a ‘relative ratio’, i.e. a multiplication factor to the default value,
    • If the given Diffusivity term is < 1.0e-4, it is assumed as the user supplied Diffusivity value


    Your Question: *What is the limiting potential (when simulating temperature)?
    Innovyze Response:
    From the Helpful this is what limiting potential represents.
    • Limiting Potential - Used to specify a limiting concentration that a chemical can either grow or decay.

      So for temperature this does not seem applicable as there appears to be no growth or decay in the basic non - MSX modeling of temperature. We would recommend to just leave as zero.

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