Buildings.Fluid.Movers

Package with fan and pump models

Information

This package contains components models for fans and pumps.

Extends from Modelica.Icons.VariantsPackage (Icon for package containing variants).

Package Content

Name Description

UsersGuide User's Guide

FlowMachine_y Fan or pump with ideally controlled normalized speed y as input signal

FlowMachine_Nrpm Fan or pump with ideally controlled speed Nrpm as input signal

FlowMachine_dp Fan or pump with ideally controlled head dp as input signal

FlowMachine_m_flow Fan or pump with ideally controlled mass flow rate as input signal

FlowMachinePolynomial Fan or pump with head and efficiency declared by a non-dimensional polynomial

Examples Collection of models that illustrate model use and test models

BaseClasses Package with base classes for Buildings.Fluid.Movers

Name	Description
UsersGuide	User's Guide
FlowMachine_y	Fan or pump with ideally controlled normalized speed y as input signal
FlowMachine_Nrpm	Fan or pump with ideally controlled speed Nrpm as input signal
FlowMachine_dp	Fan or pump with ideally controlled head dp as input signal
FlowMachine_m_flow	Fan or pump with ideally controlled mass flow rate as input signal
FlowMachinePolynomial	Fan or pump with head and efficiency declared by a non-dimensional polynomial
Examples	Collection of models that illustrate model use and test models
BaseClasses	Package with base classes for Buildings.Fluid.Movers

Buildings.Fluid.Movers.FlowMachine_y

Fan or pump with ideally controlled normalized speed y as input signal

Buildings.Fluid.Movers.FlowMachine_y

Information

This model describes a fan or pump with prescribed normalized speed. The input connector provides the normalized rotational speed (between 0 and 1). The head is computed based on the performance curve that take as an argument the actual volume flow rate divided by the maximum flow rate and the relative speed of the fan. The efficiency of the device is computed based on the efficiency curves that take as an argument the actual volume flow rate divided by the maximum possible volume flow rate, or based on the motor performance curves.

See the User's Guide for more information.

Extends from Buildings.Fluid.Movers.BaseClasses.PrescribedFlowMachine (Partial model for fan or pump with speed (y or Nrpm) as input signal).

Parameters

Type Name Default Description

replaceable package Medium PartialMedium Medium in the component

Boolean addPowerToMedium true Set to false to avoid any power (=heat and flow work) being added to medium (may give simpler equations)

VolumeFlowRate V_flow_nominal m_flow_nominal/rho_nominal Nominal volume flow rate, used for homotopy [m3/s]

Nominal condition

MassFlowRate m_flow_nominal Nominal mass flow rate [kg/s]

Initialization

MassFlowRate m_flow.start 0 Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]

Pressure dp.start 0 Pressure difference between port_a and port_b [Pa]

Real r_V.start 1 Ratio V_flow/V_flow_max = V_flow/V_flow(dp=0, N=N_nominal)

Real r_N.start 1 Ratio N/N_nominal [1]

Characteristics

Boolean use_powerCharacteristic false Use powerCharacteristic (vs. efficiencyCharacteristic)

Boolean motorCooledByFluid true If true, then motor heat is added to fluid stream

replaceable function motorEfficiency Buildings.Fluid.Movers.BaseC... Efficiency vs. normalized volume flow rate

replaceable function hydraulicEfficiency Buildings.Fluid.Movers.BaseC... Efficiency vs. normalized volume flow rate

replaceable function flowCharacteristic baseFlow Total pressure vs. V_flow characteristic at nominal speed

AngularVelocity_rpm N_nominal 1500 Nominal rotational speed for flow characteristic [1/min]

replaceable function powerCharacteristic Buildings.Fluid.Movers.BaseC... Power consumption vs. V_flow at nominal speed and density

Assumptions

Boolean allowFlowReversal system.allowFlowReversal = true to allow flow reversal, false restricts to design direction (port_a -> port_b)

Dynamics

Boolean dynamicBalance true Set to true to use a dynamic balance, which often leads to smaller systems of equations

Dynamics energyDynamics Modelica.Fluid.Types.Dynamic... Formulation of energy balance (used if dynamicBalance=true)

Time tau 1 Time constant of fluid volume for nominal flow, used if dynamicBalance=true [s]

Advanced

MassFlowRate m_flow_small 1E-4*abs(m_flow_nominal) Small mass flow rate for regularization of zero flow [kg/s]

Boolean homotopyInitialization true = true, use homotopy method

Diagnostics

Boolean show_T true = true, if actual temperature at port is computed (may lead to events)

Initialization

Boolean use_T_start true = true, use T_start, otherwise h_start

Temperature T_start if use_T_start then system.T... Start value of temperature [K]

SpecificEnthalpy h_start if use_T_start then Medium.s... Start value of inlet specific enthalpy [J/kg]

MassFraction X_start[Medium.nX] Medium.X_default Start value of mass fractions m_i/m [kg/kg]

ExtraProperty C_start[Medium.nC] fill(0, Medium.nC) Start value of trace substances

Pressure p_start Medium.p_default Start value of inlet pressure [Pa]

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium in the component
Boolean	addPowerToMedium	true	Set to false to avoid any power (=heat and flow work) being added to medium (may give simpler equations)
VolumeFlowRate	V_flow_nominal	m_flow_nominal/rho_nominal	Nominal volume flow rate, used for homotopy [m3/s]
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Initialization
MassFlowRate	m_flow.start	0	Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]
Pressure	dp.start	0	Pressure difference between port_a and port_b [Pa]
Real	r_V.start	1	Ratio V_flow/V_flow_max = V_flow/V_flow(dp=0, N=N_nominal)
Real	r_N.start	1	Ratio N/N_nominal [1]
Characteristics
Boolean	use_powerCharacteristic	false	Use powerCharacteristic (vs. efficiencyCharacteristic)
Boolean	motorCooledByFluid	true	If true, then motor heat is added to fluid stream
replaceable function motorEfficiency	Buildings.Fluid.Movers.BaseC...	Efficiency vs. normalized volume flow rate
replaceable function hydraulicEfficiency	Buildings.Fluid.Movers.BaseC...	Efficiency vs. normalized volume flow rate
replaceable function flowCharacteristic	baseFlow	Total pressure vs. V_flow characteristic at nominal speed
AngularVelocity_rpm	N_nominal	1500	Nominal rotational speed for flow characteristic [1/min]
replaceable function powerCharacteristic	Buildings.Fluid.Movers.BaseC...	Power consumption vs. V_flow at nominal speed and density
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Dynamics
Boolean	dynamicBalance	true	Set to true to use a dynamic balance, which often leads to smaller systems of equations
Dynamics	energyDynamics	Modelica.Fluid.Types.Dynamic...	Formulation of energy balance (used if dynamicBalance=true)
Time	tau	1	Time constant of fluid volume for nominal flow, used if dynamicBalance=true [s]
Advanced
MassFlowRate	m_flow_small	1E-4*abs(m_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
Boolean	homotopyInitialization	true	= true, use homotopy method
Diagnostics
Boolean	show_T	true	= true, if actual temperature at port is computed (may lead to events)
Initialization
Boolean	use_T_start	true	= true, use T_start, otherwise h_start
Temperature	T_start	if use_T_start then system.T...	Start value of temperature [K]
SpecificEnthalpy	h_start	if use_T_start then Medium.s...	Start value of inlet specific enthalpy [J/kg]
MassFraction	X_start[Medium.nX]	Medium.X_default	Start value of mass fractions m_i/m [kg/kg]
ExtraProperty	C_start[Medium.nC]	fill(0, Medium.nC)	Start value of trace substances
Pressure	p_start	Medium.p_default	Start value of inlet pressure [Pa]

Connectors

Type Name Description

FluidPort_a port_a Fluid connector a (positive design flow direction is from port_a to port_b)

FluidPort_b port_b Fluid connector b (positive design flow direction is from port_a to port_b)

HeatPort_a heatPort

input RealInput y Constant normalized rotational speed

Characteristics

replaceable function flowCharacteristic Total pressure vs. V_flow characteristic at nominal speed

Type	Name	Description
FluidPort_a	port_a	Fluid connector a (positive design flow direction is from port_a to port_b)
FluidPort_b	port_b	Fluid connector b (positive design flow direction is from port_a to port_b)
HeatPort_a	heatPort
input RealInput	y	Constant normalized rotational speed
Characteristics
replaceable function flowCharacteristic	Total pressure vs. V_flow characteristic at nominal speed

Modelica definition

model FlowMachine_y 
  "Fan or pump with ideally controlled normalized speed y as input signal"
  extends Buildings.Fluid.Movers.BaseClasses.PrescribedFlowMachine(
  final N_nominal=1500 "fix N_nominal as it is used only for scaling",
  redeclare replaceable function flowCharacteristic =
      Buildings.Fluid.Movers.BaseClasses.Characteristics.baseFlow);

  Modelica.Blocks.Interfaces.RealInput y(min=0, max=1) 
    "Constant normalized rotational speed";

equation 
  N = y*N_nominal;
end FlowMachine_y;

Buildings.Fluid.Movers.FlowMachine_Nrpm

Fan or pump with ideally controlled speed Nrpm as input signal

Buildings.Fluid.Movers.FlowMachine_Nrpm

Information

This model describes a fan or pump with prescribed speed in revolutions per minute. The head is computed based on the performance curve that take as an argument the actual volume flow rate divided by the maximum flow rate and the relative speed of the fan. The efficiency of the device is computed based on the efficiency curves that take as an argument the actual volume flow rate divided by the maximum possible volume flow rate, or based on the motor performance curves.

See the User's Guide for more information.

Extends from Buildings.Fluid.Movers.BaseClasses.PrescribedFlowMachine (Partial model for fan or pump with speed (y or Nrpm) as input signal).

Parameters

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium in the component
Boolean	addPowerToMedium	true	Set to false to avoid any power (=heat and flow work) being added to medium (may give simpler equations)
VolumeFlowRate	V_flow_nominal	m_flow_nominal/rho_nominal	Nominal volume flow rate, used for homotopy [m3/s]
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Initialization
MassFlowRate	m_flow.start	0	Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]
Pressure	dp.start	0	Pressure difference between port_a and port_b [Pa]
Real	r_V.start	1	Ratio V_flow/V_flow_max = V_flow/V_flow(dp=0, N=N_nominal)
Real	r_N.start	1	Ratio N/N_nominal [1]
Characteristics
Boolean	use_powerCharacteristic	false	Use powerCharacteristic (vs. efficiencyCharacteristic)
Boolean	motorCooledByFluid	true	If true, then motor heat is added to fluid stream
replaceable function motorEfficiency	Buildings.Fluid.Movers.BaseC...	Efficiency vs. normalized volume flow rate
replaceable function hydraulicEfficiency	Buildings.Fluid.Movers.BaseC...	Efficiency vs. normalized volume flow rate
replaceable function flowCharacteristic	baseFlow	Total pressure vs. V_flow characteristic at nominal speed
AngularVelocity_rpm	N_nominal	1500	Nominal rotational speed for flow characteristic [1/min]
replaceable function powerCharacteristic	Buildings.Fluid.Movers.BaseC...	Power consumption vs. V_flow at nominal speed and density
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Dynamics
Boolean	dynamicBalance	true	Set to true to use a dynamic balance, which often leads to smaller systems of equations
Dynamics	energyDynamics	Modelica.Fluid.Types.Dynamic...	Formulation of energy balance (used if dynamicBalance=true)
Time	tau	1	Time constant of fluid volume for nominal flow, used if dynamicBalance=true [s]
Advanced
MassFlowRate	m_flow_small	1E-4*abs(m_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
Boolean	homotopyInitialization	true	= true, use homotopy method
Diagnostics
Boolean	show_T	true	= true, if actual temperature at port is computed (may lead to events)
Initialization
Boolean	use_T_start	true	= true, use T_start, otherwise h_start
Temperature	T_start	if use_T_start then system.T...	Start value of temperature [K]
SpecificEnthalpy	h_start	if use_T_start then Medium.s...	Start value of inlet specific enthalpy [J/kg]
MassFraction	X_start[Medium.nX]	Medium.X_default	Start value of mass fractions m_i/m [kg/kg]
ExtraProperty	C_start[Medium.nC]	fill(0, Medium.nC)	Start value of trace substances
Pressure	p_start	Medium.p_default	Start value of inlet pressure [Pa]

Connectors

Type	Name	Description
FluidPort_a	port_a	Fluid connector a (positive design flow direction is from port_a to port_b)
FluidPort_b	port_b	Fluid connector b (positive design flow direction is from port_a to port_b)
HeatPort_a	heatPort
input RealInput	Nrpm	Prescribed rotational speed [1/min]

Modelica definition

model FlowMachine_Nrpm 
  "Fan or pump with ideally controlled speed Nrpm as input signal"
  extends Buildings.Fluid.Movers.BaseClasses.PrescribedFlowMachine;

  Modelica.Blocks.Interfaces.RealInput Nrpm(unit="1/min") 
    "Prescribed rotational speed";

equation 
  N = Nrpm;
end FlowMachine_Nrpm;

Buildings.Fluid.Movers.FlowMachine_dp

Fan or pump with ideally controlled head dp as input signal

Buildings.Fluid.Movers.FlowMachine_dp

Information

This model describes a fan or pump with prescribed head. The input connector provides the difference between outlet minus inlet pressure. The efficiency of the device is computed based on the efficiency curves that take as an argument the actual volume flow rate divided by the maximum possible volume flow rate.

See the User's Guide for more information.

Extends from Buildings.Fluid.Movers.BaseClasses.ControlledFlowMachine (Partial model for fan or pump with ideally controlled mass flow rate or head as input signal).

Parameters

Type Name Default Description

replaceable package Medium PartialMedium Medium in the component

Boolean addPowerToMedium true Set to false to avoid any power (=heat and flow work) being added to medium (may give simpler equations)

MassFlowRate m_flow_max m_flow_nominal Maximum mass flow rate (at zero head) [kg/s]

Boolean control_m_flow false = false to control head instead of m_flow

Nominal condition

MassFlowRate m_flow_nominal Nominal mass flow rate [kg/s]

Initialization

MassFlowRate m_flow.start 0 Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]

Pressure dp.start 0 Pressure difference between port_a and port_b [Pa]

Real r_V.start 1 Ratio V_flow/V_flow_max = V_flow/V_flow(dp=0, N=N_nominal)

Characteristics

Boolean motorCooledByFluid true If true, then motor heat is added to fluid stream

replaceable function motorEfficiency Buildings.Fluid.Movers.BaseC... Efficiency vs. normalized volume flow rate

replaceable function hydraulicEfficiency Buildings.Fluid.Movers.BaseC... Efficiency vs. normalized volume flow rate

Assumptions

Boolean allowFlowReversal system.allowFlowReversal = true to allow flow reversal, false restricts to design direction (port_a -> port_b)

Dynamics

Boolean dynamicBalance true Set to true to use a dynamic balance, which often leads to smaller systems of equations

Dynamics energyDynamics Modelica.Fluid.Types.Dynamic... Formulation of energy balance (used if dynamicBalance=true)

Time tau 1 Time constant of fluid volume for nominal flow, used if dynamicBalance=true [s]

Advanced

MassFlowRate m_flow_small 1E-4*abs(m_flow_nominal) Small mass flow rate for regularization of zero flow [kg/s]

Boolean homotopyInitialization true = true, use homotopy method

Diagnostics

Boolean show_T true = true, if actual temperature at port is computed (may lead to events)

Initialization

Boolean use_T_start true = true, use T_start, otherwise h_start

Temperature T_start if use_T_start then system.T... Start value of temperature [K]

SpecificEnthalpy h_start if use_T_start then Medium.s... Start value of inlet specific enthalpy [J/kg]

MassFraction X_start[Medium.nX] Medium.X_default Start value of mass fractions m_i/m [kg/kg]

ExtraProperty C_start[Medium.nC] fill(0, Medium.nC) Start value of trace substances

Pressure p_start Medium.p_default Start value of inlet pressure [Pa]

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium in the component
Boolean	addPowerToMedium	true	Set to false to avoid any power (=heat and flow work) being added to medium (may give simpler equations)
MassFlowRate	m_flow_max	m_flow_nominal	Maximum mass flow rate (at zero head) [kg/s]
Boolean	control_m_flow	false	= false to control head instead of m_flow
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Initialization
MassFlowRate	m_flow.start	0	Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]
Pressure	dp.start	0	Pressure difference between port_a and port_b [Pa]
Real	r_V.start	1	Ratio V_flow/V_flow_max = V_flow/V_flow(dp=0, N=N_nominal)
Characteristics
Boolean	motorCooledByFluid	true	If true, then motor heat is added to fluid stream
replaceable function motorEfficiency	Buildings.Fluid.Movers.BaseC...	Efficiency vs. normalized volume flow rate
replaceable function hydraulicEfficiency	Buildings.Fluid.Movers.BaseC...	Efficiency vs. normalized volume flow rate
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Dynamics
Boolean	dynamicBalance	true	Set to true to use a dynamic balance, which often leads to smaller systems of equations
Dynamics	energyDynamics	Modelica.Fluid.Types.Dynamic...	Formulation of energy balance (used if dynamicBalance=true)
Time	tau	1	Time constant of fluid volume for nominal flow, used if dynamicBalance=true [s]
Advanced
MassFlowRate	m_flow_small	1E-4*abs(m_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
Boolean	homotopyInitialization	true	= true, use homotopy method
Diagnostics
Boolean	show_T	true	= true, if actual temperature at port is computed (may lead to events)
Initialization
Boolean	use_T_start	true	= true, use T_start, otherwise h_start
Temperature	T_start	if use_T_start then system.T...	Start value of temperature [K]
SpecificEnthalpy	h_start	if use_T_start then Medium.s...	Start value of inlet specific enthalpy [J/kg]
MassFraction	X_start[Medium.nX]	Medium.X_default	Start value of mass fractions m_i/m [kg/kg]
ExtraProperty	C_start[Medium.nC]	fill(0, Medium.nC)	Start value of trace substances
Pressure	p_start	Medium.p_default	Start value of inlet pressure [Pa]

Connectors

Type Name Description

FluidPort_a port_a Fluid connector a (positive design flow direction is from port_a to port_b)

FluidPort_b port_b Fluid connector b (positive design flow direction is from port_a to port_b)

HeatPort_a heatPort

input RealInput m_flow_in Prescribed mass flow rate

input RealInput dp_in Prescribed outlet pressure

Type	Name	Description
FluidPort_a	port_a	Fluid connector a (positive design flow direction is from port_a to port_b)
FluidPort_b	port_b	Fluid connector b (positive design flow direction is from port_a to port_b)
HeatPort_a	heatPort
input RealInput	m_flow_in	Prescribed mass flow rate
input RealInput	dp_in	Prescribed outlet pressure

Modelica definition

model FlowMachine_dp 
  "Fan or pump with ideally controlled head dp as input signal"
  extends Buildings.Fluid.Movers.BaseClasses.ControlledFlowMachine(
  final control_m_flow = false);
equation 
  assert(dp_in >= -0.1,
    "dp_in cannot be negative. Obtained dp_in = " + realString(dp_in));

end FlowMachine_dp;

Buildings.Fluid.Movers.FlowMachine_m_flow

Fan or pump with ideally controlled mass flow rate as input signal

Buildings.Fluid.Movers.FlowMachine_m_flow

Information

This model describes a fan or pump with prescribed mass flow rate. The efficiency of the device is computed based on the efficiency curves that take as an argument the actual volume flow rate divided by the maximum possible volume flow rate.

See the User's Guide for more information.

Extends from Buildings.Fluid.Movers.BaseClasses.ControlledFlowMachine (Partial model for fan or pump with ideally controlled mass flow rate or head as input signal).

Parameters

Type Name Default Description

replaceable package Medium PartialMedium Medium in the component

Boolean addPowerToMedium true Set to false to avoid any power (=heat and flow work) being added to medium (may give simpler equations)

MassFlowRate m_flow_max m_flow_nominal Maximum mass flow rate (at zero head) [kg/s]

Boolean control_m_flow true = false to control head instead of m_flow

Nominal condition

MassFlowRate m_flow_nominal Nominal mass flow rate [kg/s]

Initialization

MassFlowRate m_flow.start 0 Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]

Pressure dp.start 0 Pressure difference between port_a and port_b [Pa]

Real r_V.start 1 Ratio V_flow/V_flow_max = V_flow/V_flow(dp=0, N=N_nominal)

Characteristics

Boolean motorCooledByFluid true If true, then motor heat is added to fluid stream

replaceable function motorEfficiency Buildings.Fluid.Movers.BaseC... Efficiency vs. normalized volume flow rate

replaceable function hydraulicEfficiency Buildings.Fluid.Movers.BaseC... Efficiency vs. normalized volume flow rate

Assumptions

Boolean allowFlowReversal system.allowFlowReversal = true to allow flow reversal, false restricts to design direction (port_a -> port_b)

Dynamics

Boolean dynamicBalance true Set to true to use a dynamic balance, which often leads to smaller systems of equations

Dynamics energyDynamics Modelica.Fluid.Types.Dynamic... Formulation of energy balance (used if dynamicBalance=true)

Time tau 1 Time constant of fluid volume for nominal flow, used if dynamicBalance=true [s]

Advanced

MassFlowRate m_flow_small 1E-4*abs(m_flow_nominal) Small mass flow rate for regularization of zero flow [kg/s]

Boolean homotopyInitialization true = true, use homotopy method

Diagnostics

Boolean show_T true = true, if actual temperature at port is computed (may lead to events)

Initialization

Boolean use_T_start true = true, use T_start, otherwise h_start

Temperature T_start if use_T_start then system.T... Start value of temperature [K]

SpecificEnthalpy h_start if use_T_start then Medium.s... Start value of inlet specific enthalpy [J/kg]

MassFraction X_start[Medium.nX] Medium.X_default Start value of mass fractions m_i/m [kg/kg]

ExtraProperty C_start[Medium.nC] fill(0, Medium.nC) Start value of trace substances

Pressure p_start Medium.p_default Start value of inlet pressure [Pa]

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium in the component
Boolean	addPowerToMedium	true	Set to false to avoid any power (=heat and flow work) being added to medium (may give simpler equations)
MassFlowRate	m_flow_max	m_flow_nominal	Maximum mass flow rate (at zero head) [kg/s]
Boolean	control_m_flow	true	= false to control head instead of m_flow
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Initialization
MassFlowRate	m_flow.start	0	Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]
Pressure	dp.start	0	Pressure difference between port_a and port_b [Pa]
Real	r_V.start	1	Ratio V_flow/V_flow_max = V_flow/V_flow(dp=0, N=N_nominal)
Characteristics
Boolean	motorCooledByFluid	true	If true, then motor heat is added to fluid stream
replaceable function motorEfficiency	Buildings.Fluid.Movers.BaseC...	Efficiency vs. normalized volume flow rate
replaceable function hydraulicEfficiency	Buildings.Fluid.Movers.BaseC...	Efficiency vs. normalized volume flow rate
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Dynamics
Boolean	dynamicBalance	true	Set to true to use a dynamic balance, which often leads to smaller systems of equations
Dynamics	energyDynamics	Modelica.Fluid.Types.Dynamic...	Formulation of energy balance (used if dynamicBalance=true)
Time	tau	1	Time constant of fluid volume for nominal flow, used if dynamicBalance=true [s]
Advanced
MassFlowRate	m_flow_small	1E-4*abs(m_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
Boolean	homotopyInitialization	true	= true, use homotopy method
Diagnostics
Boolean	show_T	true	= true, if actual temperature at port is computed (may lead to events)
Initialization
Boolean	use_T_start	true	= true, use T_start, otherwise h_start
Temperature	T_start	if use_T_start then system.T...	Start value of temperature [K]
SpecificEnthalpy	h_start	if use_T_start then Medium.s...	Start value of inlet specific enthalpy [J/kg]
MassFraction	X_start[Medium.nX]	Medium.X_default	Start value of mass fractions m_i/m [kg/kg]
ExtraProperty	C_start[Medium.nC]	fill(0, Medium.nC)	Start value of trace substances
Pressure	p_start	Medium.p_default	Start value of inlet pressure [Pa]

Connectors

Type Name Description

FluidPort_a port_a Fluid connector a (positive design flow direction is from port_a to port_b)

FluidPort_b port_b Fluid connector b (positive design flow direction is from port_a to port_b)

HeatPort_a heatPort

input RealInput m_flow_in Prescribed mass flow rate

input RealInput dp_in Prescribed outlet pressure

Type	Name	Description
FluidPort_a	port_a	Fluid connector a (positive design flow direction is from port_a to port_b)
FluidPort_b	port_b	Fluid connector b (positive design flow direction is from port_a to port_b)
HeatPort_a	heatPort
input RealInput	m_flow_in	Prescribed mass flow rate
input RealInput	dp_in	Prescribed outlet pressure

Modelica definition

model FlowMachine_m_flow 
  "Fan or pump with ideally controlled mass flow rate as input signal"
  extends Buildings.Fluid.Movers.BaseClasses.ControlledFlowMachine(
  final control_m_flow=true);
end FlowMachine_m_flow;

Buildings.Fluid.Movers.FlowMachinePolynomial

Fan or pump with head and efficiency declared by a non-dimensional polynomial

Buildings.Fluid.Movers.FlowMachinePolynomial

Information

This is a model of a flow machine (pump or fan).

The normalized pressure difference is computed using a function of the normalized mass flow rate. The function is a polynomial for which a user needs to supply the coefficients and two values that determine for what flow rate the polynomial is linearly extended.

Note: This model is here for compatibility with older versions of this library. For new models, use instead Buildings.Fluid.Movers.FlowMachine_y.

Extends from Buildings.Fluid.Interfaces.PartialStaticTwoPortInterface (Partial model transporting fluid between two ports without storing mass or energy).

Parameters

Type Name Default Description

replaceable package Medium PartialMedium Medium in the component

Length D Diameter [m]

Real a[:] Polynomial coefficients for pressure=p(mNor_flow)

Real b[:] Polynomial coefficients for etaSha=p(mNor_flow)

Real mNorMin_flow Lowest valid normalized mass flow rate

Real mNorMax_flow Highest valid normalized mass flow rate

Real scaM_flow 1 Factor used to scale the mass flow rate of the fan (used for quickly adjusting fan size)

Real scaDp 1 Factor used to scale the pressure increase of the fan (used for quickly adjusting fan size)

Nominal condition

MassFlowRate m_flow_nominal Nominal mass flow rate [kg/s]

Initialization

MassFlowRate m_flow.start 0 Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]

Pressure dp.start 0 Pressure difference between port_a and port_b [Pa]

Assumptions

Boolean allowFlowReversal system.allowFlowReversal = true to allow flow reversal, false restricts to design direction (port_a -> port_b)

Advanced

MassFlowRate m_flow_small 1E-4*abs(m_flow_nominal) Small mass flow rate for regularization of zero flow [kg/s]

Boolean homotopyInitialization true = true, use homotopy method

Diagnostics

Boolean show_V_flow false = true, if volume flow rate at inflowing port is computed

Boolean show_T false = true, if actual temperature at port is computed (may lead to events)

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium in the component
Length	D		Diameter [m]
Real	a[:]		Polynomial coefficients for pressure=p(mNor_flow)
Real	b[:]		Polynomial coefficients for etaSha=p(mNor_flow)
Real	mNorMin_flow		Lowest valid normalized mass flow rate
Real	mNorMax_flow		Highest valid normalized mass flow rate
Real	scaM_flow	1	Factor used to scale the mass flow rate of the fan (used for quickly adjusting fan size)
Real	scaDp	1	Factor used to scale the pressure increase of the fan (used for quickly adjusting fan size)
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Initialization
MassFlowRate	m_flow.start	0	Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]
Pressure	dp.start	0	Pressure difference between port_a and port_b [Pa]
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
MassFlowRate	m_flow_small	1E-4*abs(m_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
Boolean	homotopyInitialization	true	= true, use homotopy method
Diagnostics
Boolean	show_V_flow	false	= true, if volume flow rate at inflowing port is computed
Boolean	show_T	false	= true, if actual temperature at port is computed (may lead to events)

Connectors

Type	Name	Description
FluidPort_a	port_a	Fluid connector a (positive design flow direction is from port_a to port_b)
FluidPort_b	port_b	Fluid connector b (positive design flow direction is from port_a to port_b)
input RealInput	N_in	Prescribed rotational speed

Modelica definition

model FlowMachinePolynomial 
  "Fan or pump with head and efficiency declared by a non-dimensional polynomial"
  extends Buildings.Fluid.Interfaces.PartialStaticTwoPortInterface;

  Modelica.Blocks.Interfaces.RealInput N_in "Prescribed rotational speed";

  parameter Modelica.SIunits.Length D "Diameter";
  parameter Real[:] a "Polynomial coefficients for pressure=p(mNor_flow)";
  parameter Real[:] b "Polynomial coefficients for etaSha=p(mNor_flow)";
  parameter Real mNorMin_flow "Lowest valid normalized mass flow rate";
  parameter Real mNorMax_flow "Highest valid normalized mass flow rate";
  parameter Real scaM_flow = 1 
    "Factor used to scale the mass flow rate of the fan (used for quickly adjusting fan size)";
  parameter Real scaDp = 1 
    "Factor used to scale the pressure increase of the fan (used for quickly adjusting fan size)";

  Real pNor(min=0) "Normalized pressure";
  Real mNor_flow(start=mNorMax_flow) "Normalized mass flow rate";
  Real etaSha(min=0, max=1) "Efficiency, flow work divided by shaft power";
  Modelica.SIunits.Power PSha "Power input at shaft";

  Medium.Density rho "Medium density";
protected 
  parameter Real pNorMin1(fixed=false) 
    "Normalized pressure, used to test slope of polynomial outside [xMin, xMax]";
  parameter Real pNorMin2(fixed=false) 
    "Normalized pressure, used to test slope of polynomial outside [xMin, xMax]";
  parameter Real pNorMax1(fixed=false) 
    "Normalized pressure, used to test slope of polynomial outside [xMin, xMax]";
  parameter Real pNorMax2(fixed=false) 
    "Normalized pressure, used to test slope of polynomial outside [xMin, xMax]";

initial equation 
 // check slope of polynomial outside the domain [mNorMin_flow, mNorMax_flow]
 pNorMin1 = Buildings.Fluid.Utilities.extendedPolynomial(
                                        c=a, x=mNorMin_flow/2, xMin=mNorMin_flow, xMax=mNorMax_flow);
 pNorMin2 = Buildings.Fluid.Utilities.extendedPolynomial(
                                        c=a, x=mNorMin_flow, xMin=mNorMin_flow, xMax=mNorMax_flow);
 pNorMax1 = Buildings.Fluid.Utilities.extendedPolynomial(
                                        c=a, x=mNorMax_flow, xMin=mNorMin_flow, xMax=mNorMax_flow);
 pNorMax2 = Buildings.Fluid.Utilities.extendedPolynomial(
                                        c=a, x=mNorMax_flow*2, xMin=mNorMin_flow, xMax=mNorMax_flow);
 assert(pNorMin1>pNorMin2,
    "Slope of pump pressure polynomial is non-negative for mNor_flow < mNorMin_flow. Check parameter a.");
 assert(pNorMax1>pNorMax2,
    "Slope of pump pressure polynomial is non-negative for mNorMax_flow < mNor_flow. Check parameter a.");

equation 
  // For computing the density, we assume that the fan operates in the design flow direction.
  rho = Medium.density(
     Medium.setState_phX(port_a.p, inStream(port_a.h_outflow), inStream(port_a.Xi_outflow)));

  -dp = scaDp     * pNor      * rho * D*D   * N_in * N_in;
  m_flow = scaM_flow * mNor_flow * rho * D*D*D * N_in;
  pNor = Buildings.Fluid.Utilities.extendedPolynomial(
                                        c=a, x=mNor_flow, xMin=mNorMin_flow, xMax=mNorMax_flow);
  etaSha = max(0.1, Buildings.Fluid.Utilities.polynomial(
                                                      c=b, x=mNor_flow));
  etaSha * PSha = -dp * m_flow / rho; // dp<0 and m_flow>0 for normal operation

  // Energy balance (no storage, no heat loss/gain)
  PSha = -m_flow*(port_a.h_outflow-inStream(port_b.h_outflow));
  PSha = m_flow*(port_b.h_outflow-inStream(port_a.h_outflow));

  // Mass balance (no storage)
  port_a.m_flow + port_b.m_flow = 0;

  // Transport of substances
  port_a.Xi_outflow = inStream(port_b.Xi_outflow);
  port_b.Xi_outflow = inStream(port_a.Xi_outflow);

  port_a.C_outflow = inStream(port_b.C_outflow);
  port_b.C_outflow = inStream(port_a.C_outflow);

end FlowMachinePolynomial;

Automatically generated Fri May 06 14:12:35 2011.