Buildings.Fluid.FixedResistances.BaseClasses.Validation
Collection of validation models
Information
This package contains validation models for the classes in Buildings.Fluid.FixedResistances.BaseClasses.
Note that most validation models contain simple input data which may not be realistic, but for which the correct output can be obtained through an analytic solution. The examples plot various outputs, which have been verified against these solutions. These model outputs are stored as reference data and used for continuous validation whenever models in the library change.
Extends from Modelica.Icons.ExamplesPackage (Icon for packages containing runnable examples).
Package Content
| Name | Description |
|---|---|
 PlugFlowCore
|
Simple example of plug flow pipe core |
Buildings.Fluid.FixedResistances.BaseClasses.Validation.PlugFlowCore
Simple example of plug flow pipe core
Information
Basic test of model Buildings.Fluid.FixedResistances.BaseClasses.PlugFlowCore. 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 pipes | |
| Length | dh | 0.1 | Hydraulic diameter (assuming a round cross section area) [m] |
| Length | dIns | 0.05 | Thickness of pipe insulation [m] |
| ThermalConductivity | kIns | 0.028 | Heat conductivity of pipe insulation [W/(m.K)] |
| SpecificHeatCapacity | cPip | 500 | Specific heat of pipe wall material. 2300 for PE, 500 for steel [J/(kg.K)] |
| Density | rhoPip | 8000 | Density of pipe wall material. 930 for PE, 8000 for steel [kg/m3] |
| Real | R | 1/(kIns*2*Modelica.Constants... | Thermal resistance per unit length from fluid to boundary temperature |
| Real | C | rho_default*Modelica.Constan... | Thermal capacity per unit length of water in pipe |
| ThermodynamicState | sta_default | Medium.setState_pTX(T=Medium... | Default medium state |
| SpecificHeatCapacity | cp_default | Medium.specificHeatCapacityC... | Heat capacity of medium [J/(kg.K)] |
| Advanced | |||
| Density | rho_default | Medium.density_pTX(p=Medium.... | Default density (e.g., rho_liquidWater = 995, rho_air = 1.2) [kg/m3] |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package Medium | Medium in pipes | |
Modelica definition
model PlugFlowCore "Simple example of plug flow pipe core"
extends Modelica.Icons.Example;
replaceable package Medium = Buildings.Media.Water "Medium in pipes";
parameter Modelica.SIunits.Length dh=0.1
"Hydraulic diameter (assuming a round cross section area)";
parameter Modelica.SIunits.Length dIns = 0.05
"Thickness of pipe insulation";
parameter Modelica.SIunits.ThermalConductivity kIns= 0.028
"Heat conductivity of pipe insulation";
parameter Modelica.SIunits.SpecificHeatCapacity cPip=500
"Specific heat of pipe wall material. 2300 for PE, 500 for steel";
parameter Modelica.SIunits.Density rhoPip=8000
"Density of pipe wall material. 930 for PE, 8000 for steel";
parameter Real R=1/(kIns*2*Modelica.Constants.pi/
Modelica.Math.log((dh/2 + dIns)/(dh/2)))
"Thermal resistance per unit length from fluid to boundary temperature";
parameter Real C=rho_default*Modelica.Constants.pi*(
dh/2)^2*cp_default "Thermal capacity per unit length of water in pipe";
parameter Modelica.SIunits.Density rho_default=Medium.density_pTX(
p=Medium.p_default,
T=Medium.T_default,
X=Medium.X_default)
"Default density (e.g., rho_liquidWater = 995, rho_air = 1.2)";
parameter Medium.ThermodynamicState sta_default=Medium.setState_pTX(
T=Medium.T_default,
p=Medium.p_default,
X=Medium.X_default) "Default medium state";
parameter Modelica.SIunits.SpecificHeatCapacity cp_default=
Medium.specificHeatCapacityCp(state=sta_default)
"Heat capacity of medium";
Modelica.Blocks.Sources.Ramp Tin(
height=20,
duration=0,
offset=273.15 + 50,
startTime=100) "Ramp temperature 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.BaseClasses.PlugFlowCore pip(
redeclare package Medium = Medium,
from_dp=true,
dh=0.1,
length=100,
m_flow_nominal=1,
roughness=2.5e-5,
thickness=0.0032,
initDelay=true,
m_flow_start=1,
R=R,
C=C,
v_nominal=1.5,
T_start_in=323.15,
T_start_out=323.15) "Pipe";
Buildings.HeatTransfer.Sources.FixedTemperature bou(T=283.15)
"Fixed temperature boundary condition";
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(senTemOut.port_b, sin.ports[1]);
connect(sou.ports[1], senTemIn.port_a);
connect(senTemIn.port_b, pip.port_a);
connect(pip.port_b, senTemOut.port_a);
end PlugFlowCore;