OpenSimHub · dietmarw · Aug 13, 2026 · Feb 11, 2026 · Feb 17, 2026 · Feb 11, 2026
diff --git a/OpenHPL/ElectroMech/Turbines/EmpiricalTurbine.mo b/OpenHPL/ElectroMech/Turbines/EmpiricalTurbine.mo
@@ -0,0 +1,45 @@
+within OpenHPL.ElectroMech.Turbines;
+model EmpiricalTurbine
+  parameter SI.Height H_n = 100 "Nominal net head" annotation (Dialog(group = "Nominal values"));
+  parameter SI.Power P_n( displayUnit = "MW")= 1.e+06 "Nominal power"  annotation (Dialog(group = "Nominal values"));
+  extends OpenHPL.ElectroMech.BaseClasses.TorqueEquation;
+  extends OpenHPL.Interfaces.TurbineContacts;
+  extends OpenHPL.Icons.Turbine;
+
+  SI.VolumeFlowRate Vdot "Turbine flow rate";
+  SI.Pressure dp "Pressure drop";
+  SI.Torque Tt "Turbine torque";
+  Modelica.Blocks.Sources.RealExpression realExpression(y=Tt) annotation (Placement(transformation(extent={{-70,-10},{-50,10}})));
+
+  protected
+  constant Real eta0=0.90 "Full load efficiency. Hard coded at the moment. Can be parametrized in the future";
+  parameter SI.VolumeFlowRate Vdot_n=P_n/(eta0*data.rho*data.g*H_n) "Nominal discharge";
+  parameter SI.Torque Tt_n=P_n/(2*C.pi*nrps_n) "Nominal turbine torque";
+  parameter Real NQE=4.0*H_n^(-2./3.) "Specific speed based on empirical relation";
+  parameter Real kappa=max(1.351-0.857*NQE,1.05);
+  parameter Real nRA=min(1.5+NQE*5,2.6) "Normalized runaway speed as function of specific speed";
+  parameter Real dQdn=0.4222+0.3179*Modelica.Math.log(NQE);
+  parameter SI.Frequency nrps_n=2*data.f_grid/p "Nominal turbine speed [rps]";
+  SI.Frequency nrps=speedSensor.w/(2*C.pi) "Rotational speed (in revolutions per seconds)";
+  parameter Real Ct =Vdot_n/sqrt(H_n*data.g*data.rho) "Nominal turbine discharge coefficient";
+  constant Real alpha=1.5 "Empirical exponent for the guide-vane opening/discharge characteristic";
+  constant Real beta=3.5 "Empirical exponent for the normalized speed/discharge characteristic";
+  constant Real tau_1=0.1 "First parameter in empirical torque equation";
+  constant Real epsilon = 5.0e-5 "Constant to ensure robust expression for dp vs flow. Trial and error to find suitable value.";
+
+equation
+  i.mdot + o.mdot = 0;
+  i.mdot = Vdot*data.rho;
+  dp = i.p - o.p;
+  Vdot*abs(Vdot)= dp*(Ct*max(epsilon, abs(u_t)^alpha)*(1+dQdn*(max(nrps/(nrps_n*nRA),epsilon)^beta)))^2;
+  Tt=Tt_n*(Vdot/Vdot_n)*(1-tau_1*(dp/(H_n*(data.rho*data.g)))^2)*(1-(nrps/(nrps_n*nRA))^5);
+
+  connect(realExpression.y, torque.tau) annotation (Line(points={{-49,0},{-37.2,0}}, color={0,0,127}));
+annotation (Documentation(info="<html>
+<p>Simplified empirical turbine model for single-regulated reaction turbine (Francis and propeller turbine). The turbine is specified by giving the nominal head H_n and nominal power P_n. All remaining values are determined from empirical relations. The throttling effect of high head Francis turbines is included in the model. However, the exact characteristics should be treated with caution and will need more empirical tuning in future releases. In particular the speed rise and runaway curve is not fully validated.</p>
+<p align=\"center\"><img src=\"modelica://OpenHPL/Resources/Images/EmpiricalTurbine01.svg\"/></p>
+<p><em>Figure 1: Example of throttling effect for a high head Francis unit. Discharge as function of speed [pu].</em></p>
+<p align=\"center\"><img src=\"modelica://OpenHPL/Resources/Images/EmpiricalTurbine02.svg\"/></p>
+<p><em>Figure 2: Variation of turbine characteristics as function of head of the turbine characteristics. Discharge as function of speed [pu].</em></p>
+</html>"));
+end EmpiricalTurbine;
diff --git a/OpenHPL/ElectroMech/Turbines/package.order b/OpenHPL/ElectroMech/Turbines/package.order
@@ -1,3 +1,4 @@
 Turbine
 Francis
 Pelton
+EmpiricalTurbine
diff --git a/OpenHPL/Resources/Images/EmpiricalTurbine01.svg b/OpenHPL/Resources/Images/EmpiricalTurbine01.svg