• When error message has no error in it

    Hello everyone,
    I created new SST model in Modelica that is based on the Plosz SST model in MSL library.
    Now I identify all the typos and wrong variable declatations by trying to run a simple simualtion with this new model and analyzing error message that popped up.
    It went pretty smooth until an error message had actually no defined error in it. Instead there's a long list of all functions and variables in this particular project (in attatchment).
    Does anybody had similar experience and know where might be the problem?

     
  • Re: Lack of correct initialization in some blocks. (As example PI).

    Hello,
    I have a similar issue and didn't find a solution yet. I want [u]steady-state [b]u[/b][/u] value to be the [u]initial [b]u[/b] for dynamic simulation[/u].
    I had a look at PI controller MSL file I couldn't find a line where initial conditions are defined - but what was obvious from my simulations is that initial [b]u[/b] was [b]u[sub]max[/sub][/b]. Why is that? And how I could copy steady-state [b]u[/b] to dynamic simulation?
    My dynaminc simulation period is quite short so when [b]initial u[/b] is [b]u[sub]max[/sub][/b] it introduces quite a big interferences.

    Natalia
  • Re: Issues with dynamic simulations of secondary seetling

    Hi Enrico,
    model modifications I was mentioning in the first post were put on hold. I was working with MLS library but then at the end of a year decided to upgrade to WEST+ and work on Modelica from now on. Since there are some issues with SST model I want to work with in Modelica library, I decided to go back to MSL.
    As I changed a bit research plans and I don't plan to perform long term simulations my first question is not valid anymore.
    Coming back to the second question: I assume I have to declare a new class which would be a TSS concentration in all leyers at time O? Is that correct? If so, is this procedure similar in both MSL and Modelica (like placement of new parameter definition etc.).  Anyhow, I would definitely need help in creating those new models.

    Additinally another question came along (similar in topic) - I have dynamic data for SST model validation (inflow and underflow - Q and TSS- and SBH). So I wanted to modify SST model so as an input I can have direct TSS values and not ASM fractions. I assume follwing code lines in SST models have to be changed:
    in Modelica
    [i]Help_X_In = [new defined input vector] [s]sum(Inflow[i] for i in zModWWTP.TComponentsTSS) * (if size(zModWWTP.TComponentsTSS,1) > 1  then F_TSS_COD else 1)[/s];
    X_In = if (Q_In <= 0.0) then 0.0 else Help_X_In / [s]Q_In ;[/s][/i]
    in MSL (base.clarifier file)
    [i]state.Help_X_In = [new defined input vector][s](SUMOVER Comp_Index IN {IndexOfFirstTSSComponent .. IndexOfLastTSSComponent}:
                        (interface.Inflow[Comp_Index]))[/s];

        {state.X_In = IF (state.Q_In == 0)
              THEN 0
              ELSE state.Help_X_In [s]/ state.Q_In * parameters.F_TSS_COD;[/s][/i]
    And of course similarly for X_Out.
    Am I even close to the right solution?

    Regards,
    Natalia
  • Issues with dynamic simulations of secondary seetling

    Hello everyone,
    I have a few issues revolving conducting simulations of SST and would appretiate any input from other users who maybe were confronted with similar problems.
    I. Is there a way to conduct a long-term dynamic simualtion with alternating settling parameters of activated sludge - to mimic filamentous growth during winter months? Other then conducting a series of dynamic simulations and manually adjusting r_H, r_P or v0?
    II. To simulate batch settling tests I wanted to declare a uniform initial concentration across all leyers of SST and then start dynamic simulation with no feed and no under- and overflow. And I failed in finding a way to impose a user-declared values for state variables. Is there a way to do that other then creating a new model?

    With regards,
    Natalia