Modelica.Fluid.Machines

Devices for converting between energy held in a fluid and mechanical energy

Information



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

Package Content

NameDescription
Modelica.Fluid.Machines.SweptVolume SweptVolume varying cylindric volume depending on the position of the piston
Modelica.Fluid.Machines.Pump Pump Centrifugal pump with mechanical connector for the shaft
Modelica.Fluid.Machines.ControlledPump ControlledPump Centrifugal pump with ideally controlled mass flow rate
Modelica.Fluid.Machines.PrescribedPump PrescribedPump Centrifugal pump with ideally controlled speed
Modelica.Fluid.Machines.BaseClasses BaseClasses Base classes used in the Machines package (only of interest to build new component models)

Modelica.Fluid.Machines.SweptVolume Modelica.Fluid.Machines.SweptVolume

varying cylindric volume depending on the position of the piston

Information


Mixing volume with varying size. The size of the volume is given by:

Losses are neglected. The shaft power is completely converted into mechanical work on the fluid.

The flange position has to be equal or greater than zero. Otherwise the simulation stops. The force of the flange results from the pressure difference between medium and ambient pressure and the cross sectional piston area. For using the component, a top level instance of the ambient model with the inner attribute is needed.

The pressure at both fluid ports equals the medium pressure in the volume. No suction nor discharge valve is included in the model.

The thermal port is directly connected to the medium. The temperature of the thermal port equals the medium temperature. The heat capacity of the cylinder and the piston are not includes in the model.

Extends from Modelica.Fluid.Vessels.BaseClasses.PartialLumpedVessel (Lumped volume with a vector of fluid ports and replaceable heat transfer model).

Parameters

NameDescription
pistonCrossAreacross sectional area of piston [m2]
clearanceremaining volume at zero piston stroke [m3]
replaceable package MediumMedium in the component
fluidVolumeVolume [m3]
Ports
use_portsData= false to neglect pressure loss and kinetic energy
portsData[if use_portsData then nPorts else 0]Data of inlet/outlet ports
Assumptions
Dynamics
energyDynamicsFormulation of energy balance
massDynamicsFormulation of mass balance
Heat transfer
use_HeatTransfer= true to use the HeatTransfer model
replaceable model HeatTransferWall heat transfer
Initialization
p_startStart value of pressure [Pa]
use_T_start= true, use T_start, otherwise h_start
T_startStart value of temperature [K]
h_startStart value of specific enthalpy [J/kg]
X_start[Medium.nX]Start value of mass fractions m_i/m [kg/kg]
C_start[Medium.nC]Start value of trace substances
Advanced
Port properties
m_flow_nominalNominal value for mass flow rates in ports [kg/s]
m_flow_smallRegularization range at zero mass flow rate [kg/s]
use_Re= true, if turbulent region is defined by Re, otherwise by m_flow_small

Connectors

NameDescription
ports[nPorts]Fluid inlets and outlets
heatPort 
flangetranslation flange for piston

Modelica.Fluid.Machines.Pump Modelica.Fluid.Machines.Pump

Centrifugal pump with mechanical connector for the shaft

Information


This model describes a centrifugal pump (or a group of nParallel pumps) with a mechanical rotational connector for the shaft, to be used when the pump drive has to be modelled explicitly. In the case of nParallel pumps, the mechanical connector is relative to a single pump.

The model extends PartialPump

Extends from Modelica.Fluid.Machines.BaseClasses.PartialPump (Base model for centrifugal pumps).

Parameters

NameDescription
replaceable package MediumMedium in the component
Characteristics
nParallelNumber of pumps in parallel
replaceable function flowCharacteristicHead vs. V_flow characteristic at nominal speed and density
N_nominalNominal rotational speed for flow characteristic [1/min]
rho_nominalNominal fluid density for characteristic [kg/m3]
use_powerCharacteristicUse powerCharacteristic (vs. efficiencyCharacteristic)
replaceable function powerCharacteristicPower consumption vs. V_flow at nominal speed and density
replaceable function efficiencyCharacteristicEfficiency vs. V_flow at nominal speed and density
Assumptions
allowFlowReversal= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
checkValve= true to prevent reverse flow
VVolume inside the pump [m3]
Dynamics
energyDynamicsFormulation of energy balance
massDynamicsFormulation of mass balance
Heat transfer
use_HeatTransfer= true to use a HeatTransfer model, e.g., for a housing
replaceable model HeatTransferWall heat transfer
Initialization
p_a_startGuess value for inlet pressure [Pa]
p_b_startGuess value for outlet pressure [Pa]
m_flow_startGuess value of m_flow = port_a.m_flow [kg/s]
use_T_start= true, use T_start, otherwise h_start
T_startStart value of temperature [K]
h_startStart value of specific enthalpy [J/kg]
X_start[Medium.nX]Start value of mass fractions m_i/m [kg/kg]
C_start[Medium.nC]Start value of trace substances
Advanced
Diagnostics
replaceable model MonitoringOptional pump monitoring

Connectors

NameDescription
port_aFluid connector a (positive design flow direction is from port_a to port_b)
port_bFluid connector b (positive design flow direction is from port_a to port_b)
heatPort 
shaft 

Modelica.Fluid.Machines.ControlledPump Modelica.Fluid.Machines.ControlledPump

Centrifugal pump with ideally controlled mass flow rate

Information


This model describes a centrifugal pump (or a group of nParallel pumps) with ideally controlled mass flow rate or pressure.

Nominal values are used to predefine an exemplary pump characteristics and to define the operation of the pump. The input connectors m_flow_set or p_set can optionally be enabled to provide time varying set points.

Use this model if the pump characteristics is of secondary interest. The actual characteristics can be configured later on for the appropriate rotational speed N. Then the model can be replaced with a Pump with rotational shaft or with a PrescribedPump.

Extends from Modelica.Fluid.Machines.BaseClasses.PartialPump (Base model for centrifugal pumps).

Parameters

NameDescription
replaceable package MediumMedium in the component
p_a_nominalNominal inlet pressure for predefined pump characteristics [Pa]
p_b_nominalNominal outlet pressure, fixed if not control_m_flow and not use_p_set [Pa]
m_flow_nominalNominal mass flow rate, fixed if control_m_flow and not use_m_flow_set [kg/s]
control_m_flow= false to control outlet pressure port_b.p instead of m_flow
use_m_flow_set= true to use input signal m_flow_set instead of m_flow_nominal
use_p_set= true to use input signal p_set instead of p_b_nominal
Characteristics
nParallelNumber of pumps in parallel
replaceable function flowCharacteristicHead vs. V_flow characteristic at nominal speed and density
N_nominalNominal rotational speed for flow characteristic [1/min]
rho_nominalNominal fluid density for characteristic [kg/m3]
use_powerCharacteristicUse powerCharacteristic (vs. efficiencyCharacteristic)
replaceable function powerCharacteristicPower consumption vs. V_flow at nominal speed and density
replaceable function efficiencyCharacteristicEfficiency vs. V_flow at nominal speed and density
Assumptions
allowFlowReversal= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
checkValve= true to prevent reverse flow
VVolume inside the pump [m3]
Dynamics
energyDynamicsFormulation of energy balance
massDynamicsFormulation of mass balance
Heat transfer
use_HeatTransfer= true to use a HeatTransfer model, e.g., for a housing
replaceable model HeatTransferWall heat transfer
Initialization
p_a_startGuess value for inlet pressure [Pa]
p_b_startGuess value for outlet pressure [Pa]
m_flow_startGuess value of m_flow = port_a.m_flow [kg/s]
use_T_start= true, use T_start, otherwise h_start
T_startStart value of temperature [K]
h_startStart value of specific enthalpy [J/kg]
X_start[Medium.nX]Start value of mass fractions m_i/m [kg/kg]
C_start[Medium.nC]Start value of trace substances
Advanced
Diagnostics
replaceable model MonitoringOptional pump monitoring

Connectors

NameDescription
port_aFluid connector a (positive design flow direction is from port_a to port_b)
port_bFluid connector b (positive design flow direction is from port_a to port_b)
heatPort 
m_flow_setPrescribed mass flow rate
p_setPrescribed outlet pressure
Characteristics
replaceable function flowCharacteristicHead vs. V_flow characteristic at nominal speed and density

Modelica.Fluid.Machines.PrescribedPump Modelica.Fluid.Machines.PrescribedPump

Centrifugal pump with ideally controlled speed

Information


This model describes a centrifugal pump (or a group of nParallel pumps) with prescribed speed, either fixed or provided by an external signal.

The model extends PartialPump

If the N_in input connector is wired, it provides rotational speed of the pumps (rpm); otherwise, a constant rotational speed equal to n_const (which can be different from N_nominal) is assumed.

Extends from Modelica.Fluid.Machines.BaseClasses.PartialPump (Base model for centrifugal pumps).

Parameters

NameDescription
replaceable package MediumMedium in the component
use_N_inGet the rotational speed from the input connector
N_constConstant rotational speed [1/min]
Characteristics
nParallelNumber of pumps in parallel
replaceable function flowCharacteristicHead vs. V_flow characteristic at nominal speed and density
N_nominalNominal rotational speed for flow characteristic [1/min]
rho_nominalNominal fluid density for characteristic [kg/m3]
use_powerCharacteristicUse powerCharacteristic (vs. efficiencyCharacteristic)
replaceable function powerCharacteristicPower consumption vs. V_flow at nominal speed and density
replaceable function efficiencyCharacteristicEfficiency vs. V_flow at nominal speed and density
Assumptions
allowFlowReversal= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
checkValve= true to prevent reverse flow
VVolume inside the pump [m3]
Dynamics
energyDynamicsFormulation of energy balance
massDynamicsFormulation of mass balance
Heat transfer
use_HeatTransfer= true to use a HeatTransfer model, e.g., for a housing
replaceable model HeatTransferWall heat transfer
Initialization
p_a_startGuess value for inlet pressure [Pa]
p_b_startGuess value for outlet pressure [Pa]
m_flow_startGuess value of m_flow = port_a.m_flow [kg/s]
use_T_start= true, use T_start, otherwise h_start
T_startStart value of temperature [K]
h_startStart value of specific enthalpy [J/kg]
X_start[Medium.nX]Start value of mass fractions m_i/m [kg/kg]
C_start[Medium.nC]Start value of trace substances
Advanced
Diagnostics
replaceable model MonitoringOptional pump monitoring

Connectors

NameDescription
port_aFluid connector a (positive design flow direction is from port_a to port_b)
port_bFluid connector b (positive design flow direction is from port_a to port_b)
heatPort 
N_inPrescribed rotational speed [1/min]

Automatically generated Mon Sep 23 17:20:47 2013.