Modelica.Thermal.FluidHeatFlow.Sources

Ideal fluid sources, e.g., ambient, volume flow

Information

This package contains different types of sources:

Ambient with constant or prescribed pressure and temperature
AbsolutePressure to define pressure level of a closed cooling cycle.
Constant and prescribed volume flow
Constant and prescribed pressure increase
Simple pump with mechanical flange

Thermodynamic equations are defined in partial models (package Interfaces.Partials).
All fans / pumps are considered without losses, they do not change enthalpy flow.

Main Authors:

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

Dr.Christian Kral
Österreichisches Forschungs- und Prüfzentrum Arsenal Ges.m.b.H.
arsenal research
Giefinggasse 2
A-1210 Vienna, Austria

The Modelica package is free software; it can be redistributed and/or modified under the terms of the Modelica license, see the license conditions and the accompanying disclaimer here.

Extends from Modelica.Icons.Library2 (Icon for library where additional icon elements shall be added).

Package Content

Name Description

Ambient Ambient with constant properties

AbsolutePressure Defines absolute pressure level

VolumeFlow Enforces constant volume flow

PressureIncrease Enforces constant pressure increase

IdealPump Model of an ideal pump

Name	Description
Ambient	Ambient with constant properties
AbsolutePressure	Defines absolute pressure level
VolumeFlow	Enforces constant volume flow
PressureIncrease	Enforces constant pressure increase
IdealPump	Model of an ideal pump

Modelica.Thermal.FluidHeatFlow.Sources.Ambient

Ambient with constant properties

Modelica.Thermal.FluidHeatFlow.Sources.Ambient

Information

(Infinite) ambient with constant pressure and temperature.
Thermodynamic equations are defined by Partials.Ambient.

Extends from Interfaces.Partials.Ambient (Partial model of ambient).

Parameters

Type Name Default Description

Medium medium FluidHeatFlow.Media.Medium() Ambient medium

Boolean usePressureInput false enable / disable pressure input

Pressure constantAmbientPressure Ambient pressure [Pa]

Boolean useTemperatureInput false enable / disable temperature input

Temperature constantAmbientTemperature Ambient temperature [K]

Type	Name	Default	Description
Medium	medium	FluidHeatFlow.Media.Medium()	Ambient medium
Boolean	usePressureInput	false	enable / disable pressure input
Pressure	constantAmbientPressure		Ambient pressure [Pa]
Boolean	useTemperatureInput	false	enable / disable temperature input
Temperature	constantAmbientTemperature		Ambient temperature [K]

Connectors

Type Name Description

FlowPort_a flowPort

input RealInput ambientPressure

input RealInput ambientTemperature

Type	Name	Description
FlowPort_a	flowPort
input RealInput	ambientPressure
input RealInput	ambientTemperature

Modelica definition

model Ambient "Ambient with constant properties"

  extends Interfaces.Partials.Ambient;
  parameter Boolean usePressureInput=false "enable / disable pressure input";
  parameter Modelica.SIunits.Pressure constantAmbientPressure(start=0) 
    "Ambient pressure";
  parameter Boolean useTemperatureInput=false 
    "enable / disable temperature input";
  parameter Modelica.SIunits.Temperature constantAmbientTemperature(start=293.15, displayUnit="degC") 
    "Ambient temperature";
  Modelica.Blocks.Interfaces.RealInput ambientPressure if usePressureInput;
  Modelica.Blocks.Interfaces.RealInput ambientTemperature if useTemperatureInput;
protected 
  Modelica.Blocks.Sources.Constant constPressure(final k=
        constantAmbientPressure) if not usePressureInput;
  Modelica.Blocks.Interfaces.RealInput pAmbient;
  Modelica.Blocks.Sources.Constant constTemperature(final k=
        constantAmbientTemperature) if not useTemperatureInput;
  Modelica.Blocks.Interfaces.RealInput TAmbient;
equation 
  flowPort.p = pAmbient;
  T = TAmbient;
  connect(ambientPressure, pAmbient);
  connect(ambientTemperature, TAmbient);
  connect(constPressure.y, pAmbient);
  connect(constTemperature.y, TAmbient);
end Ambient;

Modelica.Thermal.FluidHeatFlow.Sources.AbsolutePressure

Defines absolute pressure level

Modelica.Thermal.FluidHeatFlow.Sources.AbsolutePressure

Information

AbsolutePressure to define pressure level of a closed cooling cycle. Coolant's mass flow, temperature and enthalpy flow are not affected.

Parameters

Type Name Default Description

Medium medium FluidHeatFlow.Media.Medium() medium

Pressure p Pressure ground [Pa]

Type	Name	Default	Description
Medium	medium	FluidHeatFlow.Media.Medium()	medium
Pressure	p		Pressure ground [Pa]

Connectors

Type Name Description

FlowPort_a flowPort

Type	Name	Description
FlowPort_a	flowPort

Modelica definition

model AbsolutePressure "Defines absolute pressure level"

  parameter FluidHeatFlow.Media.Medium medium=FluidHeatFlow.Media.Medium() 
    "medium";
  parameter Modelica.SIunits.Pressure p(start=0) "Pressure ground";
  Interfaces.FlowPort_a flowPort(final medium=medium);
equation 
  // defining pressure
  flowPort.p = p;
  // no energy exchange; no mass flow by default
  flowPort.H_flow = 0;
end AbsolutePressure;

Modelica.Thermal.FluidHeatFlow.Sources.VolumeFlow

Enforces constant volume flow

Modelica.Thermal.FluidHeatFlow.Sources.VolumeFlow

Information

Fan resp. pump with constant volume flow rate. Pressure increase is the response of the whole system. Coolant's temperature and enthalpy flow are not affected.
Setting parameter m (mass of medium within fan/pump) to zero leads to neglection of temperature transient cv*m*der(T).
Thermodynamic equations are defined by Partials.TwoPort.

Extends from Interfaces.Partials.TwoPort (Partial model of two port).

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

Boolean useVolumeFlowInput false enable / disable volume flow input

VolumeFlowRate constantVolumeFlow Volume flow rate [m3/s]

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
Boolean	useVolumeFlowInput	false	enable / disable volume flow input
VolumeFlowRate	constantVolumeFlow		Volume flow rate [m3/s]

Connectors

Type Name Description

FlowPort_a flowPort_a

FlowPort_b flowPort_b

input RealInput volumeFlow

Type	Name	Description
FlowPort_a	flowPort_a
FlowPort_b	flowPort_b
input RealInput	volumeFlow

Modelica definition

model VolumeFlow "Enforces constant volume flow"

  extends Interfaces.Partials.TwoPort(final tapT=1);
  parameter Boolean useVolumeFlowInput=false 
    "enable / disable volume flow input";
  parameter Modelica.SIunits.VolumeFlowRate constantVolumeFlow(start=1) 
    "Volume flow rate";
  Modelica.Blocks.Interfaces.RealInput volumeFlow if useVolumeFlowInput;
protected 
  Modelica.Blocks.Sources.Constant constVolumeFlow(final k=constantVolumeFlow) if 
       not useVolumeFlowInput;
  Modelica.Blocks.Interfaces.RealInput internalVolumeFlow;
equation 
  Q_flow = 0;
  V_flow = internalVolumeFlow;
  connect(volumeFlow, internalVolumeFlow);
  connect(constVolumeFlow.y, internalVolumeFlow);
end VolumeFlow;

Modelica.Thermal.FluidHeatFlow.Sources.PressureIncrease

Enforces constant pressure increase

Modelica.Thermal.FluidHeatFlow.Sources.PressureIncrease

Information

Fan resp. pump with constant pressure increase. Mass resp. volume flow is the response of the whole system. Coolant's temperature and enthalpy flow are not affected.
Setting parameter m (mass of medium within fan/pump) to zero leads to neglection of temperature transient cv*m*der(T).
Thermodynamic equations are defined by Partials.TwoPort.

Extends from Interfaces.Partials.TwoPort (Partial model of two port).

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

Boolean usePressureIncreaseInput false enable / disable pressure increase input

Pressure constantPressureIncrease Pressure increase [Pa]

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
Boolean	usePressureIncreaseInput	false	enable / disable pressure increase input
Pressure	constantPressureIncrease		Pressure increase [Pa]

Connectors

Type Name Description

FlowPort_a flowPort_a

FlowPort_b flowPort_b

input RealInput pressureIncrease

Type	Name	Description
FlowPort_a	flowPort_a
FlowPort_b	flowPort_b
input RealInput	pressureIncrease

Modelica definition

model PressureIncrease "Enforces constant pressure increase"

  extends Interfaces.Partials.TwoPort(final tapT=1);
  parameter Boolean usePressureIncreaseInput=false 
    "enable / disable pressure increase input";
  parameter Modelica.SIunits.Pressure constantPressureIncrease(start=1) 
    "Pressure increase";
  Modelica.Blocks.Interfaces.RealInput pressureIncrease if usePressureIncreaseInput;
protected 
  Modelica.Blocks.Sources.Constant constPressureIncrease(final k=
        constantPressureIncrease) if not usePressureIncreaseInput;
  Modelica.Blocks.Interfaces.RealInput internalPressureIncrease;
equation 
  Q_flow = 0;
  dp = -internalPressureIncrease;
  connect(pressureIncrease, internalPressureIncrease);
  connect(constPressureIncrease.y, internalPressureIncrease);
end PressureIncrease;

Modelica.Thermal.FluidHeatFlow.Sources.IdealPump

Model of an ideal pump

Modelica.Thermal.FluidHeatFlow.Sources.IdealPump

Information

Simple fan resp. pump where characteristic is dependent on shaft's speed,
torque * speed = pressure increase * volume flow (without losses)
Pressure increase versus volume flow is defined by a linear function, from dp0(V_flow=0) to V_flow0(dp=0).
The axis intersections vary with speed as follows:

dp prop. speed^2
V_flow prop. speed

Coolant's temperature and enthalpy flow are not affected.
Setting parameter m (mass of medium within fan/pump) to zero leads to neglection of temperature transient cv*m*der(T).
Thermodynamic equations are defined by Partials.TwoPort.

Extends from Interfaces.Partials.TwoPort (Partial model of two port).

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

Pump characteristic

AngularVelocity wNominal Nominal speed [rad/s]

Pressure dp0 Max. pressure increase @ V_flow=0 [Pa]

VolumeFlowRate V_flow0 Max. volume flow rate @ dp=0 [m3/s]

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
Pump characteristic
AngularVelocity	wNominal		Nominal speed [rad/s]
Pressure	dp0		Max. pressure increase @ V_flow=0 [Pa]
VolumeFlowRate	V_flow0		Max. volume flow rate @ dp=0 [m3/s]

Connectors

Type Name Description

FlowPort_a flowPort_a

FlowPort_b flowPort_b

Flange_a flange_a

Type	Name	Description
FlowPort_a	flowPort_a
FlowPort_b	flowPort_b
Flange_a	flange_a

Modelica definition

model IdealPump "Model of an ideal pump"

  extends Interfaces.Partials.TwoPort(final tapT=1);
  parameter Modelica.SIunits.AngularVelocity wNominal(start=1, displayUnit="1/min") 
    "Nominal speed";
  parameter Modelica.SIunits.Pressure dp0(start=2) 
    "Max. pressure increase @ V_flow=0";
  parameter Modelica.SIunits.VolumeFlowRate V_flow0(start=2) 
    "Max. volume flow rate @ dp=0";
  Modelica.SIunits.AngularVelocity w=der(flange_a.phi) "Speed";
protected 
  Modelica.SIunits.Pressure dp1;
  Modelica.SIunits.VolumeFlowRate V_flow1;
public 
  Modelica.Mechanics.Rotational.Interfaces.Flange_a flange_a;
equation 
  // pump characteristic
  dp1 = dp0*sign(w/wNominal)*(w/wNominal)^2;
  V_flow1 = V_flow0*(w/wNominal);
  if noEvent(abs(w)<Modelica.Constants.small) then
    dp = 0;
    flange_a.tau = 0;
  else
    dp = -dp1*(1-noEvent(abs(V_flow/V_flow1)));
    flange_a.tau*w = -dp*V_flow;
  end if;
  // no energy exchange with medium
  Q_flow = 0;
end IdealPump;

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