modelPartialPump
Information
This is the base model for pumps strongly inspired from the PartialPump of Modelica Standard Library (MSL).
The pump model is based on the theory of kinematic similarity: the pump characteristics are given for nominal operating conditions (rotational speed and fluid density), and then adapted to actual operating condition, according to the similarity equations.
Pump characteristics
The nominal hydraulic characteristic (head vs. volume flow rate) is given by the replaceable function flowCharacteristic.
The pump energy balance can be specified in two alternative ways:
use_powerCharacteristic = false(default option): the replaceable functionefficiencyCharacteristic(efficiency vs. volume flow rate in nominal conditions) is used to determine the efficiency, and then the power consumption. The default is a constant efficiency of 0.8.use_powerCharacteristic = true: the replaceable functionpowerCharacteristic(power consumption vs. volume flow rate in nominal conditions) is used to determine the power consumption, and then the efficiency. UsepowerCharacteristicto specify a non-zero power consumption for zero flow rate.
Several functions are provided in the package PumpCharacteristics of the TAeZoSysPro library or the MSL to specify the characteristics as a function of some operating points at nominal conditions.
Depending on the value of the checkValve parameter, the model either supports reverse flow conditions, or includes a built-in check valve to avoid flow reversal.
Dynamics options
The pump dynamic is quasistatic. No mass or energy are stored.
Heat transfer
The pump is adiabatic.
Diagnostics of Cavitation
The replaceable Monitoring submodel can be configured to PumpMonitoringNPSH, in order to compute the Net Positive Suction Head available and check for cavitation, provided a two-phase medium model is used (see Advanced tab).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.SIunits.Acceleration | g | Constants.g_n | |
| Assumptions | |||
| Boolean | checkValve | false | = true to prevent reverse flow |
| Characteristics | |||
| Modelica.SIunits.Conversions.NonSIunits.AngularVelocity_rpm | N_nominal | Nominal rotational speed for flow characteristic | |
| Medium.Density | d_nominal | Medium.density_pTX(Medium.p_default, Medium.T_default, Medium.X_default) | Nominal fluid density for characteristic |
| Boolean | use_powerCharacteristic | false | Use powerCharacteristic (vs. efficiencyCharacteristic) |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | port_a | ||
| Modelica.Fluid.Interfaces.FluidPort_b | port_b |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.SIunits.VolumeFlowRate | V_flow | Volume flow rate at port_a | |
| Modelica.SIunits.MassFlowRate | m_flow | Mass flow rate | |
| Modelica.SIunits.Power | P | Power given to the fluid | |
| Modelica.SIunits.Density | d | Density at port_a | |
| Modelica.SIunits.Position | head | Pump head | |
| Modelica.SIunits.PressureDifference | dp | Pressure difference between port_a and port_b | |
| Modelica.SIunits.Efficiency | eta | Isentropic efficiency | |
| Modelica.SIunits.Conversions.NonSIunits.AngularVelocity_rpm | N | Shaft rotational speed | |
| Medium.ThermodynamicState | state | State at inlet |
Contents
| Name | Description |
|---|---|
 Medium | |
 flowCharacteristic | Head vs. V_flow characteristic at nominal speed and density |
 powerCharacteristic | Power consumption vs. V_flow at nominal speed and density |
 efficiencyCharacteristic |
Revisions
- 8 Jan 2013
by Rüdiger Franke:
moved NPSH diagnostics from PartialPump to replaceable sub-model PumpMonitoring.PumpMonitoringNPSH (see ticket #646) - Dec 2008
by Rüdiger Franke:
- Replaced simplified mass and energy balances with rigorous formulation (base class PartialLumpedVolume)
- Introduced optional HeatTransfer model defining Qb_flow
- Enabled events when the checkValve is operating to support the opening of a discrete valve before port_a
- 31 Oct 2005
by Francesco Casella:
Model added to the Fluid library