Hi Chris,

Seems to simulate fine anyway except that the fluid is at the absolute zero temperature in valve.
You have make your own closed tank.
Why not use closed tank object of Modelica's Fluid  library ?

I am going to study your script, it's very interesting to understand how to use/create mixture medium.


/Bruno

Hi
"The request can't be found" this is the popup message I can read when I try to upload a png image or a pdf document.
What's wrong ?
/Bruno

Hi,
I try to make new Fluid device model by embedding from standards Fluid devices models. I have a difficulty to understand how to pass Medium properties (inheritance process).
I have this issue : " Medium is partial, name lookup is not allowed in partial classes"
An example : I try to make a very simple pipe (by hidding  most of parameters) from static pipe to use with my students.

model SimplePipe

// extends ?

  parameter Real L = 1 "Length (m)" annotation(Evaluate = true);

  Modelica.Fluid.Pipes.StaticPipe pipe(replaceable package Medium = Medium,  diameter = 1, length = L)  annotation(
    Placement(visible = true, transformation(origin = {2, 0}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
  Modelica.Fluid.Interfaces.FluidPort_a port_a annotation(
    Placement(visible = true, transformation(origin = {-100, 0}, extent = {{-10, -10}, {10, 10}}, rotation = 0), iconTransformation(origin = {-100, 0}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
  Modelica.Fluid.Interfaces.FluidPort_b port_b annotation(
    Placement(visible = true, transformation(origin = {100, 0}, extent = {{-10, -10}, {10, 10}}, rotation = 0), iconTransformation(origin = {102, 0}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
equation
  connect(port_a, pipe.port_a) annotation(
    Line(points = {{-100, 0}, {-8, 0}}));
  connect(pipe.port_b, port_b) annotation(
    Line(points = {{12, 0}, {100, 0}}, color = {0, 127, 255}));

annotation(
    uses(Modelica(version = "3.2.3")),
    Icon(graphics = {Rectangle(fillColor = {0, 0, 255}, fillPattern = FillPattern.Solid, extent = {{-80, 40}, {80, -40}}), Line(origin = {-69.01, -19.09}, points = {{-28.9893, 19.0923}, {-10.9893, 19.0923}}, color = {0, 0, 255}, thickness = 1), Line(origin = {57, -32.97}, points = {{23, 32.9667}, {37, 32.9667}}, color = {0, 0, 255}, thickness = 1), Line(origin = {-0.707068, 14.1414}, points = {{55, -85}, {-60, -85}}, color = {0, 128, 255}), Polygon(origin = {0, 14}, lineColor = {255, 255, 255}, fillColor = {255, 255, 255}, fillPattern = FillPattern.Solid, points = {{20, -75}, {50, -85}, {20, -95}, {20, -75}}), Polygon(origin = {0, 14}, lineColor = {0, 128, 255}, fillColor = {0, 128, 255}, fillPattern = FillPattern.Solid, points = {{20, -70}, {60, -85}, {20, -100}, {20, -70}})}));
end

ysseraviva.fr/Images/SimplePipe.png

Thank's  (adrpo)


Regards

/Bruno

Hi All,

Some graphical objects have no more visible port B connector in the fluid library.
It's the same with Linux and W$ (I've not test yet with MAC OS)
The library is then unusable.
So it's now  the mess with connections in my previous schematics.
This seems to affect new and old : pipe, valve, pump, fitting, source and my own specific industrial process control Library
Previous tanks are "auto replaced by pump" !

I have created a ticket for that.

Have a good day

/Bruno

PS:
Can someone explain me please how to upload a picture ? "Attachments" don't works with me

Hello,


I'm relatively a newbie with Modelica, but not in process control (closed loop control) and simulation. I have  experimented that limit management is sometime tricky.
You must always simulate a real system, not an ideal one that could lead for instance  to infinite currents, zero times responses etc. and with realistic initial conditions.

/Bruno

PS:  to simulate Converters, I think you better can use PSPICE like softs (it's less sexy but more efficient than OpenModelica). LTspice is free.

Hi all,

I have created a block PT (pressure transmitter) to give the measure of fluid pressure with some options.
It can deliver absolute pressure as bar a or effective pressure as bar g ( = absolute pressure - atmospheric pressure )
When I put on the graphical sheet of Omedit model a system block, I can then  use the global variable system.p_ambient everywhere.
In the definition of PT block, I have the line:
  type Press = Real(final quantity = "Pressure");
parameter Press Ambient_Pressure = system.p_ambient "Pressure reference (Pa a)";

(or .system.p_ambient)


That causes a compilation error (unknown variable), but if I enter system.p_ambient in instanced object it runs well.

As well, there is no error with  a constant like parameter Press Ambient_Pressure = 101325 "Pressure reference (Pa a)";

An idea ?

/Bruno

Thanks Adeel to have corrected the grapical bugs on valves, open Tank  and fuid sources on the new 1.16.1 openmodelica last version
/Bruno

Hello Adeel,

Thank's for your quick response.

Take a look at https://trac.openmodelica.org/OpenModelica/ticket/6166

On bug2.zip you willl see that after double clicking on object, connectors appears, but, not drawings.


/Bruno

PS: why is it impossible for me to upload images in the forum ? (Firefox in Linux Mint 19)

Hi all,

Fluid library don't work correctly any more (at least the graphical part) for 1.16 either in Linux (mint 19 mint 20) or Windows (7 10) .
Have a look at attachments.
I'm surprised that no one had notice it
Have a good day

/Bruno

...  SORRY: IMPOSSIBLE TO ADD (even small)  ANY PICTURE IN ATTACHMENTS ...