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Implement isobaric expansion coefficient for incompressible media #245

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27 changes: 27 additions & 0 deletions ThermofluidStream/Media/myMedia/Incompressible.mo
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Original file line number Diff line number Diff line change
Expand Up @@ -392,6 +392,21 @@ which is only exactly true for a fluid with constant density d=d0.
annotation(smoothOrder=2);
end thermalConductivity;

redeclare function extends isobaricExpansionCoefficient
"Return isobaric expansion coefficient (beta) as a function of the thermodynamic state record"
algorithm
beta := -density_derT_p(state) / density(state);
annotation(
Documentation(info = "<html><head></head><body><p>The isobaric expansion coefficient <code>beta</code> is defined as</p>
<blockquote><pre>1/v * der(v,T)
</pre></blockquote>
<p>with <code>v</code> = <code>1/d</code>, at constant pressure <code>p</code>.
Using the chain rule:</p>
<blockquote><pre>1/v * der(v,T) = d * (-der(d, T) / d^2)
= -der(d, T) / d</pre><pre><br></pre></blockquote>
</body></html>"));
end isobaricExpansionCoefficient;

function s_T "Compute specific entropy"
extends Modelica.Icons.Function;
input Temperature T "Temperature";
Expand Down Expand Up @@ -498,6 +513,18 @@ which is only exactly true for a fluid with constant density d=d0.
ddph :=0; //incompressable and h = cp*T; h=const; -> T=const
end density_derp_h;

redeclare function extends density_derh_p
"Return density derivative w.r.t. specific enthalpy at constant pressure"
algorithm
ddhp := density_derT_p(state) / specificHeatCapacityCp(state);
end density_derh_p;

redeclare function extends density_derT_p
"Return density derivative w.r.t. temperature at constant pressure"
algorithm
ddTp := Polynomials.derivativeValue(poly_rho, if TinK then state.T else Cv.to_degC(state.T));
end density_derT_p;

redeclare function extends specificEnthalpy
"Return specific enthalpy as a function of the thermodynamic state record"
algorithm
Expand Down