Modelica.Thermal.FluidHeatFlow.Interfaces.Partials

Partial models

Information

This package contains partial models, defining in a very compact way the basic thermodynamic equations used by the different components.

Main Authors:

Anton Haumer
Technical Consulting & Electrical Engineering
A-3423 St.Andrae-Woerdern, Austria
email: a.haumer@haumer.at

Dr. Christian Kral
Austrian Institute of Technology, AIT
Giefinggasse 2
A-1210 Vienna, Austria

This Modelica package is free software and the use is completely at your own risk; it can be redistributed and/or modified under the terms of the Modelica License 2. For license conditions (including the disclaimer of warranty) see Modelica.UsersGuide.ModelicaLicense2 or visit http://www.modelica.org/licenses/ModelicaLicense2.

Extends from Modelica.Icons.Package (Icon for standard packages).

Package Content

Name Description

SimpleFriction Simple friction model

TwoPort Partial model of two port

Ambient Partial model of ambient

AbsoluteSensor Partial model of absolute sensor

RelativeSensor Partial model of relative sensor

FlowSensor Partial model of flow sensor

Name	Description
SimpleFriction	Simple friction model
TwoPort	Partial model of two port
Ambient	Partial model of ambient
AbsoluteSensor	Partial model of absolute sensor
RelativeSensor	Partial model of relative sensor
FlowSensor	Partial model of flow sensor

Modelica.Thermal.FluidHeatFlow.Interfaces.Partials.SimpleFriction

Simple friction model

Modelica.Thermal.FluidHeatFlow.Interfaces.Partials.SimpleFriction

Information

Definition of relationship between pressure drop and volume flow rate:
-V_flowLaminar < VolumeFlow < +V_flowLaminar: laminar i.e., linear dependency of pressure drop on volume flow.
-V_flowLaminar > VolumeFlow or VolumeFlow < +V_flowLaminar: turbulent i.e., quadratic dependency of pressure drop on volume flow.
Linear and quadratic dependency are coupled smoothly at V_flowLaminar / dpLaminar.
Quadratic dependency is defined by nominal volume flow and pressure drop (V_flowNominal / dpNominal).
See also sketch at diagram layer.

Parameters

Type Name Default Description

Simple Friction

VolumeFlowRate V_flowLaminar Laminar volume flow [m3/s]

Pressure dpLaminar Laminar pressure drop [Pa]

VolumeFlowRate V_flowNominal Nominal volume flow [m3/s]

Pressure dpNominal Nominal pressure drop [Pa]

Real frictionLoss 0 Part of friction losses fed to medium

Type	Name	Default	Description
Simple Friction
VolumeFlowRate	V_flowLaminar		Laminar volume flow [m3/s]
Pressure	dpLaminar		Laminar pressure drop [Pa]
VolumeFlowRate	V_flowNominal		Nominal volume flow [m3/s]
Pressure	dpNominal		Nominal pressure drop [Pa]
Real	frictionLoss	0	Part of friction losses fed to medium

Modelica definition

partial model SimpleFriction "Simple friction model"

  parameter Modelica.SIunits.VolumeFlowRate V_flowLaminar(min=Modelica.Constants.small, start=0.1) 
    "Laminar volume flow";
  parameter Modelica.SIunits.Pressure dpLaminar(start=0.1) 
    "Laminar pressure drop";
  parameter Modelica.SIunits.VolumeFlowRate V_flowNominal(start=1) 
    "Nominal volume flow";
  parameter Modelica.SIunits.Pressure dpNominal(start=1) 
    "Nominal pressure drop";
  parameter Real frictionLoss(min=0, max=1) = 0 
    "Part of friction losses fed to medium";
  Modelica.SIunits.Pressure pressureDrop;
  Modelica.SIunits.VolumeFlowRate volumeFlow;
  Modelica.SIunits.Power Q_friction;
protected 
  parameter Modelica.SIunits.Pressure dpNomMin=dpLaminar/V_flowLaminar*V_flowNominal;
  parameter Real k(final unit="Pa.s2/m6", fixed=false);
initial algorithm 
  assert(V_flowNominal>V_flowLaminar,
    "SimpleFriction: V_flowNominal has to be > V_flowLaminar!");
  assert(dpNominal>=dpNomMin,
    "SimpleFriction: dpNominal has to be > dpLaminar/V_flowLaminar*V_flowNominal!");
  k:=(dpNominal - dpNomMin)/(V_flowNominal - V_flowLaminar)^2;
equation 
  if     volumeFlow > +V_flowLaminar then
    pressureDrop = +dpLaminar/V_flowLaminar*volumeFlow + k*(volumeFlow - V_flowLaminar)^2;
  elseif volumeFlow < -V_flowLaminar then
    pressureDrop = +dpLaminar/V_flowLaminar*volumeFlow - k*(volumeFlow + V_flowLaminar)^2;
  else
    pressureDrop =  dpLaminar/V_flowLaminar*volumeFlow;
  end if;
  Q_friction = frictionLoss*volumeFlow*pressureDrop;
end SimpleFriction;

Modelica.Thermal.FluidHeatFlow.Interfaces.Partials.TwoPort

Partial model of two port

Modelica.Thermal.FluidHeatFlow.Interfaces.Partials.TwoPort

Information

Partial model with two flowPorts.
Possible heat exchange with the ambient is defined by Q_flow; setting this = 0 means no energy exchange.
Setting parameter m (mass of medium within pipe) to zero leads to neglection of temperature transient cv*m*der(T).
Mixing rule is applied.
Parameter 0 < tapT < 1 defines temperature of heatPort between medium's inlet and outlet temperature.

Parameters

Type Name Default Description

Medium medium FluidHeatFlow.Media.Medium() Medium in the component

Mass m Mass of medium [kg]

Temperature T0 Initial temperature of medium [K]

Real tapT 1 Defines temperature of heatPort between inlet and outlet temperature

Type	Name	Default	Description
Medium	medium	FluidHeatFlow.Media.Medium()	Medium in the component
Mass	m		Mass of medium [kg]
Temperature	T0		Initial temperature of medium [K]
Real	tapT	1	Defines temperature of heatPort between inlet and outlet temperature

Connectors

Type Name Description

FlowPort_a flowPort_a

FlowPort_b flowPort_b

Type	Name	Description
FlowPort_a	flowPort_a
FlowPort_b	flowPort_b

Modelica definition

partial model TwoPort "Partial model of two port"

  parameter FluidHeatFlow.Media.Medium medium=FluidHeatFlow.Media.Medium() 
    "Medium in the component";
  parameter Modelica.SIunits.Mass m(start=1) "Mass of medium";
  parameter Modelica.SIunits.Temperature T0(start=293.15, displayUnit="degC") 
    "Initial temperature of medium";
  parameter Real tapT(final min=0, final max=1)=1 
    "Defines temperature of heatPort between inlet and outlet temperature";
  Modelica.SIunits.Pressure dp=flowPort_a.p - flowPort_b.p "Pressure drop a->b";
  Modelica.SIunits.VolumeFlowRate V_flow=flowPort_a.m_flow/medium.rho 
    "Volume flow a->b";
  Modelica.SIunits.HeatFlowRate Q_flow "Heat exchange with ambient";
  output Modelica.SIunits.Temperature T(start=T0) 
    "Outlet temperature of medium";
  output Modelica.SIunits.Temperature T_a=flowPort_a.h/medium.cp 
    "Temperature at flowPort_a";
  output Modelica.SIunits.Temperature T_b=flowPort_b.h/medium.cp 
    "Temperature at flowPort_b";
  output Modelica.SIunits.TemperatureDifference dT=if noEvent(V_flow>=0) then T-T_a else T_b-T 
    "Temperature increase of coolant in flow direction";
protected 
  Modelica.SIunits.SpecificEnthalpy h = medium.cp*T 
    "Medium's specific enthalpy";
  Modelica.SIunits.Temperature T_q = T  - noEvent(sign(V_flow))*(1 - tapT)*dT 
    "Temperature relevant for heat exchange with ambient";
public 
  Interfaces.FlowPort_a flowPort_a(final medium=medium);
  Interfaces.FlowPort_b flowPort_b(final medium=medium);
equation 
  // mass balance
  flowPort_a.m_flow + flowPort_b.m_flow = 0;
  // energy balance
  if m>Modelica.Constants.small then
    flowPort_a.H_flow + flowPort_b.H_flow + Q_flow = m*medium.cv*der(T);
  else
    flowPort_a.H_flow + flowPort_b.H_flow + Q_flow = 0;
  end if;
  // massflow a->b mixing rule at a, energy flow at b defined by medium's temperature
  // massflow b->a mixing rule at b, energy flow at a defined by medium's temperature
  flowPort_a.H_flow = semiLinear(flowPort_a.m_flow,flowPort_a.h,h);
  flowPort_b.H_flow = semiLinear(flowPort_b.m_flow,flowPort_b.h,h);
end TwoPort;

Modelica.Thermal.FluidHeatFlow.Interfaces.Partials.Ambient

Partial model of ambient

Modelica.Thermal.FluidHeatFlow.Interfaces.Partials.Ambient

Information

Partial model of (Infinite) ambient, defines pressure and temperature.

Parameters

Type Name Default Description

Medium medium FluidHeatFlow.Media.Medium() Ambient medium

Type	Name	Default	Description
Medium	medium	FluidHeatFlow.Media.Medium()	Ambient medium

Connectors

Type Name Description

FlowPort_a flowPort

Type	Name	Description
FlowPort_a	flowPort

Modelica definition

partial model Ambient "Partial model of ambient"

  parameter FluidHeatFlow.Media.Medium medium=FluidHeatFlow.Media.Medium() 
    "Ambient medium";
  output Modelica.SIunits.Temperature T "Outlet temperature of medium";
  output Modelica.SIunits.Temperature T_port=flowPort.h/medium.cp 
    "Temperature at flowPort_a";
protected 
  Modelica.SIunits.SpecificEnthalpy h = medium.cp*T;
public 
  Interfaces.FlowPort_a flowPort(final medium=medium);
equation 
  // massflow -> ambient: mixing rule
  // massflow <- ambient: energy flow defined by ambient's temperature
  flowPort.H_flow = semiLinear(flowPort.m_flow,flowPort.h,h);
end Ambient;

Modelica.Thermal.FluidHeatFlow.Interfaces.Partials.AbsoluteSensor

Partial model of absolute sensor

Modelica.Thermal.FluidHeatFlow.Interfaces.Partials.AbsoluteSensor

Information

Partial model for an absolute sensor (pressure/temperature).
Pressure, mass flow, temperature and enthalpy flow of medium are not affected.

Parameters

Type Name Default Description

Medium medium FluidHeatFlow.Media.Medium() Sensor's medium

Type	Name	Default	Description
Medium	medium	FluidHeatFlow.Media.Medium()	Sensor's medium

Connectors

Type Name Description

FlowPort_a flowPort

output RealOutput y

Type	Name	Description
FlowPort_a	flowPort
output RealOutput	y

Modelica definition

partial model AbsoluteSensor "Partial model of absolute sensor"

  parameter FluidHeatFlow.Media.Medium medium=FluidHeatFlow.Media.Medium() 
    "Sensor's medium";
  Interfaces.FlowPort_a flowPort(final medium=medium);
  Modelica.Blocks.Interfaces.RealOutput y;
equation 
  // no mass exchange
  flowPort.m_flow = 0;
  // no energy exchange
  flowPort.H_flow = 0;
end AbsoluteSensor;

Modelica.Thermal.FluidHeatFlow.Interfaces.Partials.RelativeSensor

Partial model of relative sensor

Modelica.Thermal.FluidHeatFlow.Interfaces.Partials.RelativeSensor

Information

Partial model for a relative sensor (pressure drop/temperature difference).
Pressure, mass flow, temperature and enthalpy flow of medium are not affected.

Parameters

Type Name Default Description

Medium medium FluidHeatFlow.Media.Medium() Sensor's medium

Type	Name	Default	Description
Medium	medium	FluidHeatFlow.Media.Medium()	Sensor's medium

Connectors

Type Name Description

FlowPort_a flowPort_a

FlowPort_b flowPort_b

output RealOutput y

Type	Name	Description
FlowPort_a	flowPort_a
FlowPort_b	flowPort_b
output RealOutput	y

Modelica definition

partial model RelativeSensor "Partial model of relative sensor"

  parameter FluidHeatFlow.Media.Medium medium=FluidHeatFlow.Media.Medium() 
    "Sensor's medium";
  Interfaces.FlowPort_a flowPort_a(final medium=medium);
  Interfaces.FlowPort_b flowPort_b(final medium=medium);
  Modelica.Blocks.Interfaces.RealOutput y;
equation 
  // no mass exchange
  flowPort_a.m_flow = 0;
  flowPort_b.m_flow = 0;
  // no energy exchange
  flowPort_a.H_flow = 0;
  flowPort_b.H_flow = 0;
end RelativeSensor;

Modelica.Thermal.FluidHeatFlow.Interfaces.Partials.FlowSensor

Partial model of flow sensor

Modelica.Thermal.FluidHeatFlow.Interfaces.Partials.FlowSensor

Information

Partial model for a flow sensor (mass flow/heat flow).
Pressure, mass flow, temperature and enthalpy flow of medium are not affected, but mixing rule is applied.

Extends from TwoPort (Partial model of two port).

Parameters

Type Name Default Description

Medium medium FluidHeatFlow.Media.Medium() Medium in the component

Mass m 0 Mass of medium [kg]

Temperature T0 0 Initial temperature of medium [K]

Real tapT 1 Defines temperature of heatPort between inlet and outlet temperature

Type	Name	Default	Description
Medium	medium	FluidHeatFlow.Media.Medium()	Medium in the component
Mass	m	0	Mass of medium [kg]
Temperature	T0	0	Initial temperature of medium [K]
Real	tapT	1	Defines temperature of heatPort between inlet and outlet temperature

Connectors

Type Name Description

FlowPort_a flowPort_a

FlowPort_b flowPort_b

output RealOutput y

Type	Name	Description
FlowPort_a	flowPort_a
FlowPort_b	flowPort_b
output RealOutput	y

Modelica definition

partial model FlowSensor "Partial model of flow sensor"

  extends TwoPort(final m=0, final T0=0, final tapT=1);
  Modelica.Blocks.Interfaces.RealOutput y;
equation 
  // no pressure drop
  dp = 0;
  // no energy exchange
  Q_flow = 0;
end FlowSensor;

Automatically generated Fri Nov 12 16:31:44 2010.