Buildings.Fluid.FixedResistances.Examples
Collection of models that illustrate model use and test models
Information
This package contains examples for the use of models that can be found in Buildings.Fluid.FixedResistances.
Extends from Modelica.Icons.ExamplesPackage (Icon for packages containing runnable examples).
Package Content
| Name | Description |
|---|---|
 FlowJunction
|
Test model for the three way splitter/mixer model |
| HydraulicDiameter
|
Example model for flow resistance with hydraulic diameter as parameter |
| Pipe
|
Test of a pipe with multiple segments |
| PlugFlowPipe
|
Simple example of plug flow pipe |
| PressureDrop
|
Example model for flow resistance with nominal pressure drop as parameter |
Buildings.Fluid.FixedResistances.Examples.FlowJunction
Test model for the three way splitter/mixer model
Information
This model demonstrates the use of the flow junction model for different flow directions. The example is configured such that the flow changes its direction in each flow leg between t = 0 seconds to t = 100 seconds.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model FlowJunction
"Test model for the three way splitter/mixer model"
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Air "Medium model";
Buildings.Fluid.FixedResistances.Junction spl(
redeclare package Medium = Medium,
m_flow_nominal={1,2,3},
dp_nominal={5,10,15},
energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial) "Splitter";
Buildings.Fluid.Sources.Boundary_pT bou1(
redeclare package Medium = Medium,
T=273.15 + 10,
use_p_in=true,
nPorts=1)
"Pressure boundary condition";
Buildings.Fluid.Sources.Boundary_pT bou2(
redeclare package Medium = Medium,
T=273.15 + 20,
p(displayUnit="Pa") = 101325,
nPorts=1)
"Pressure boundary condition";
Buildings.Fluid.Sources.Boundary_pT bou3(
redeclare package Medium = Medium,
T=273.15 + 30,
use_p_in=true,
nPorts=1)
"Pressure boundary condition";
Modelica.Blocks.Sources.Ramp P1(
offset=101320,
height=10,
duration=20,
startTime=20)
"Ramp pressure signal";
Modelica.Blocks.Sources.Ramp P3(
offset=101320,
height=10,
duration=20,
startTime=70)
"Ramp pressure signal";
Buildings.Fluid.Sensors.TemperatureTwoPort senTem1(
redeclare package Medium = Medium,
m_flow_nominal=1)
"Temperature sensor";
Buildings.Fluid.Sensors.TemperatureTwoPort senTem2(
redeclare package Medium = Medium,
m_flow_nominal=2)
"Temperature sensor";
Buildings.Fluid.Sensors.TemperatureTwoPort senTem3(
redeclare package Medium = Medium,
m_flow_nominal=3)
"Temperature sensor";
equation
connect(P1.y, bou1.p_in);
connect(bou3.p_in, P3.y);
connect(bou3.ports[1], senTem3.port_a);
connect(senTem3.port_b, spl.port_3);
connect(bou1.ports[1], senTem1.port_a);
connect(senTem1.port_b, spl.port_1);
connect(spl.port_2, senTem2.port_a);
connect(senTem2.port_b, bou2.ports[1]);
end FlowJunction;
Buildings.Fluid.FixedResistances.Examples.HydraulicDiameter
Example model for flow resistance with hydraulic diameter as parameter
Information
Example model for a fixed resistance that takes as a parameter the hydraulic diameter.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model HydraulicDiameter
"Example model for flow resistance with hydraulic diameter as parameter"
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Water "Medium model";
Modelica.Blocks.Sources.Ramp P(
duration=1,
height=4000,
offset=300000 - 2000)
"Ramp pressure signal";
Buildings.Fluid.Sources.Boundary_pT sou(
redeclare package Medium = Medium,
T=273.15 + 20,
use_p_in=true,
nPorts=2)
"Pressure boundary condition";
Buildings.Fluid.Sources.Boundary_pT sin(
redeclare package Medium = Medium,
T=273.15 + 10,
nPorts=2,
p(displayUnit="Pa") = 300000)
"Pressure boundary condition";
Buildings.Fluid.FixedResistances.HydraulicDiameter res(
redeclare package Medium = Medium,
m_flow_nominal=0.2,
v_nominal=1,
from_dp=true,
length=1)
"Fixed resistance with specified hydraulic diameter";
Buildings.Fluid.FixedResistances.HydraulicDiameter resLarPip(
redeclare package Medium = Medium,
from_dp=true,
m_flow_nominal=10,
length=100)
"Fixed resistance with specified hydraulic diameter of a large pipe";
equation
connect(P.y, sou.p_in);
connect(sou.ports[1], res.port_a);
connect(res.port_b, sin.ports[1]);
connect(resLarPip.port_a, sou.ports[2]);
connect(resLarPip.port_b, sin.ports[2]);
end HydraulicDiameter;
Buildings.Fluid.FixedResistances.Examples.Pipe
Test of a pipe with multiple segments
Information
This model demonstrates the use of a pipe model.
Both pipe models have the same mass flow rates and temperatures.
Otherwise, the assert block would terminate the simulation.
The model on the top is connected to the ambient with one heat port, whereas the model at the bottom uses a vector of heat ports. Since they are all connected to the same temperature, they result in the same energy balance for the medium that flows through the pipe.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | Buildings.Media.Water | ||
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package Medium | ||
Modelica definition
model Pipe "Test of a pipe with multiple segments"
extends Modelica.Icons.Example;
replaceable package Medium = Buildings.Media.Water;
Modelica.Blocks.Sources.Ramp P(
duration=1,
height=2*pip.dp_nominal,
offset=101325 - pip.dp_nominal);
Buildings.Fluid.Sources.Boundary_pT sou(
redeclare package Medium = Medium,
use_p_in=true,
T=273.15 + 50,
nPorts=2);
Buildings.Fluid.Sources.Boundary_pT sin(
redeclare package Medium = Medium,
T=273.15 + 10,
nPorts=2,
use_p_in=false,
p(displayUnit="Pa") = 101325);
HeatTransfer.Sources.FixedTemperature TEnv(T=263.15);
Buildings.Fluid.FixedResistances.Pipe pip(
thicknessIns=0.01,
lambdaIns=0.01,
m_flow_nominal=10,
redeclare package Medium = Medium,
length=10,
energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial);
HeatTransfer.Sources.FixedTemperature TEnv1[10](each T=263.15);
Buildings.Fluid.FixedResistances.Pipe pip1(
thicknessIns=0.01,
lambdaIns=0.01,
m_flow_nominal=10,
redeclare package Medium = Medium,
length=10,
useMultipleHeatPorts=true,
energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial);
Buildings.Fluid.Sensors.TemperatureTwoPort senTem(redeclare package Medium =
Medium, m_flow_nominal=pip.m_flow_nominal) "Temperature sensor";
Buildings.Fluid.Sensors.TemperatureTwoPort senTem1(redeclare package Medium =
Medium, m_flow_nominal=pip.m_flow_nominal) "Temperature sensor";
Buildings.Utilities.Diagnostics.AssertEquality assEqu;
equation
connect(P.y, sou.p_in);
connect(sou.ports[1], pip.port_a);
connect(TEnv.port, pip.heatPort);
connect(sou.ports[2], pip1.port_a);
connect(TEnv1.port, pip1.heatPorts);
connect(pip.port_b, senTem.port_a);
connect(senTem.port_b, sin.ports[1]);
connect(pip1.port_b, senTem1.port_a);
connect(senTem1.port_b, sin.ports[2]);
connect(assEqu.u1, senTem.T);
connect(senTem1.T, assEqu.u2);
end Pipe;
Buildings.Fluid.FixedResistances.Examples.PlugFlowPipe
Simple example of plug flow pipe
Information
Basic test of model Buildings.Fluid.FixedResistances.PlugFlowPipe. This test includes an inlet temperature step under a constant mass flow rate.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | Buildings.Media.Water | Medium in the pipe | |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package Medium | Medium in the pipe | |
Modelica definition
model PlugFlowPipe "Simple example of plug flow pipe"
extends Modelica.Icons.Example;
replaceable package Medium = Buildings.Media.Water "Medium in the pipe";
Modelica.Blocks.Sources.Ramp Tin(
height=20,
duration=0,
offset=273.15 + 50,
startTime=100) "Ramp pressure signal";
Sources.Boundary_pT sin(
redeclare package Medium = Medium,
T=273.15 + 10,
nPorts=1,
p(displayUnit="Pa") = 101325) "Pressure boundary condition";
Buildings.Fluid.FixedResistances.PlugFlowPipe pip(
redeclare package Medium = Medium,
nPorts=1,
dh=0.1,
length=100,
dIns=0.05,
kIns=0.028,
m_flow_nominal=1,
cPip=500,
thickness=0.0032,
initDelay=true,
m_flow_start=1,
rhoPip=8000,
T_start_in=323.15,
T_start_out=323.15) "Pipe";
Buildings.HeatTransfer.Sources.FixedTemperature bou(T=283.15)
"Boundary temperature";
Buildings.Fluid.Sources.MassFlowSource_T sou(
nPorts=1,
redeclare package Medium = Medium,
use_T_in=true,
m_flow=3) "Flow source";
Buildings.Fluid.Sensors.TemperatureTwoPort senTemOut(
redeclare package Medium = Medium,
m_flow_nominal=1,
T_start=323.15) "Temperature sensor";
Buildings.Fluid.Sensors.TemperatureTwoPort senTemIn(
redeclare package Medium = Medium,
m_flow_nominal=1,
T_start=323.15) "Temperature sensor";
equation
connect(bou.port, pip.heatPort);
connect(Tin.y, sou.T_in);
connect(pip.ports_b[1], senTemOut.port_a);
connect(senTemOut.port_b, sin.ports[1]);
connect(sou.ports[1], senTemIn.port_a);
connect(senTemIn.port_b, pip.port_a);
end PlugFlowPipe;
Buildings.Fluid.FixedResistances.Examples.PressureDrop
Example model for flow resistance with nominal pressure drop as parameter
Information
Example model for a fixed resistance that takes as a parameter the pressure drop at nominal condition.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model PressureDrop
"Example model for flow resistance with nominal pressure drop as parameter"
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Air "Medium model";
Modelica.Blocks.Sources.Ramp P(
duration=1,
height=20,
offset=101325 - 10) "Ramp pressure signal";
Buildings.Fluid.Sources.Boundary_pT sou(
redeclare package Medium = Medium,
T=273.15 + 20,
use_p_in=true,
nPorts=1)
"Pressure boundary condition";
Buildings.Fluid.Sources.Boundary_pT sin(
redeclare package Medium = Medium,
T=273.15 + 10,
nPorts=1,
p(displayUnit="Pa") = 101325)
"Pressure boundary condition";
Buildings.Fluid.FixedResistances.PressureDrop res(
redeclare package Medium = Medium,
m_flow_nominal=0.2,
from_dp=true,
dp_nominal=10)
"Fixed resistance";
equation
connect(P.y, sou.p_in);
connect(sou.ports[1], res.port_a);
connect(res.port_b, sin.ports[1]);
end PressureDrop;