Model of a flow junction with an optional fixed resistance in each flow leg and an optional mixing volume at the junction.

The pressure drop is implemented using the model Buildings.Fluid.FixedResistances.PressureDrop. If its nominal pressure drop is set to zero, then the pressure drop model will be removed. For example, the pressure drop declaration

  m_flow_nominal={ 0.1, 0.1,  -0.2},
  dp_nominal =   {500,    0, -6000}

would model a flow mixer that has the nominal flow rates and associated pressure drops as shown in the figure below. Note that port_3 is set to negative values. The negative values indicate that at the nominal conditions, fluid is leaving the component.


If energyDynamics <> Modelica.Fluid.Types.Dynamics.SteadyState, then at the flow junction, a fluid volume is modeled. The fluid volume is implemented using the model Buildings.Fluid.Delays.DelayFirstOrder. The fluid volume has the size

  V = sum(abs(m_flow_nominal[:])/3)*tau/rho_nominal

where tau is a parameter and rho_nominal is the density of the medium in the volume at nominal condition. Setting energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial can help reducing the size of the nonlinear system of equations.


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