Buildings.Fluid.BaseClasses.FlowModels.Examples

Information

This package contains examples for the use of models that can be found in Buildings.Fluid.BaseClasses.FlowModels.

Package Content

Name	Description
InverseFlowFunction	Test model for flow function and its inverse
TestFlowFunctions	Test model for flow functions

Buildings.Fluid.BaseClasses.FlowModels.Examples.InverseFlowFunction

Information

This model tests the inverse formulation of the flow functions. The pressure difference dp and dpCalc need to be equal up to the solver tolerance, except for a small neighborhood around the origin. In this neighborhood around the origin, the functions Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_dp and Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_m_flow are not invertible.

Parameters

Type	Name	Default	Description
Real	k	0.5
MassFlowRate	m_flow_nominal	1	Nominal flow rate [kg/s]

Modelica definition

model InverseFlowFunction 
  "Test model for flow function and its inverse"
  extends Modelica.Icons.Example;
 Modelica.SIunits.MassFlowRate m_flow;
 Modelica.SIunits.Pressure dp(displayUnit="Pa") "Pressure difference";
 Modelica.SIunits.Pressure dpCalc(displayUnit="Pa") 
    "Pressure difference computed by the flow functions";
 Modelica.SIunits.Pressure deltaDp(displayUnit="Pa") 
    "Pressure difference between input and output to the functions";
 Modelica.SIunits.Time dTime= 2;
 parameter Real k = 0.5;
 parameter Modelica.SIunits.MassFlowRate m_flow_nominal = 1 "Nominal flow rate";
equation 
  dp = (time-0.5)/dTime * 20;
  m_flow=FlowModels.basicFlowFunction_dp(dp=dp, k=k, m_flow_turbulent=m_flow_nominal*0.3);
  dpCalc=FlowModels.basicFlowFunction_m_flow(m_flow=m_flow, k=k, m_flow_turbulent=m_flow_nominal*0.3);
  deltaDp = dp - dpCalc;
end InverseFlowFunction;

Buildings.Fluid.BaseClasses.FlowModels.Examples.TestFlowFunctions

Information

Parameters

Type	Name	Default	Description
Pressure	p2	101325	Boundary condition [Pa]
Boolean	from_dp	true
Real	k	0.5
MassFlowRate	m_flow_nominal	1	Nominal flow rate [kg/s]

Modelica definition

model TestFlowFunctions "Test model for flow functions"
  extends Modelica.Icons.Example;
 Modelica.SIunits.MassFlowRate m1_flow;
 Modelica.SIunits.MassFlowRate m2_flow;
 Modelica.SIunits.Pressure dp1;
 Modelica.SIunits.Pressure dp2;
 Modelica.SIunits.Pressure p1_nominal=101325;
 Modelica.SIunits.Time dTime= 1;
 Modelica.SIunits.Pressure p1 "Boundary condition";
 parameter Modelica.SIunits.Pressure p2 = 101325 "Boundary condition";
 parameter Boolean from_dp = true;
 parameter Real k = 0.5;
 parameter Modelica.SIunits.MassFlowRate m_flow_nominal = 1 "Nominal flow rate";
equation 
  p1 = p1_nominal + (time-0.5)/dTime * 20;
  m1_flow = m2_flow;
  p2-p1 = dp1 + dp2;
  if from_dp then
  m1_flow=FlowModels.basicFlowFunction_dp(dp=dp1, k=k, m_flow_turbulent=m_flow_nominal*0.3);
  m2_flow=FlowModels.basicFlowFunction_dp(dp=dp2, k=k, m_flow_turbulent=m_flow_nominal*0.3);
  else
  dp1=FlowModels.basicFlowFunction_m_flow(m_flow=m1_flow, k=k, m_flow_turbulent=m_flow_nominal*0.3);
  dp2=FlowModels.basicFlowFunction_m_flow(m_flow=m2_flow, k=k, m_flow_turbulent=m_flow_nominal*0.3);
  end if;
  assert(abs(dp1-dp2) < 1E-5, "Error in implementation.");
end TestFlowFunctions;