Markus,

Your question is a bit unclear to me. If you just want to look up medium properties of gaseous nitrogen, use the following code:

  package N2 = Modelica.Media.IdealGases.SingleGases.N2 "Short name N2";

  N2.ThermodynamicState state = N2.setState_pT(p,T) "Assuming that you have pressure and temperature as state variables";

  N2.ThermalConductivity lambda = N2.thermalConductivity(state);

  N2.DynamicViscosity mu = N2.dynamicViscosity(state);

  N2.SpecificHeatCapacity cp = N2.specificHeatCapacityCp(state);

  N2.Density rho = N2.density(state);

Best regards,
Rene Just Nielsen

Hello justnielson,

i tried to use your code for the properties of N2.
But in my case it didn't work as well.

I want to programm a horizontal surface with natural convection. And it always asks me for the temperature. But I want to give it the fix-temperature on the left and on right side of the surface and not just one fix temperature for both sides.

But I don't know how to tell Modelica, that it uses the properties for the current temperature.

I would be pleased, if you could help me.

Best regards

Alexxx

Hi Alexxx,

It sounds to me as if you need a discretized model of your surface with N horizontal cells/control volumes to make up a temperature profile in two directions. If that is your case you must decide on a discretization scheme for your problem and look up the medium properties at each temperature in a cell.

Best regards,
Rene Just Nielsen