WOLFRAM SYSTEMMODELER

PrescribedPump

Centrifugal pump with ideally controlled speed

Diagram

Wolfram Language

In[1]:=
SystemModel["Modelica.Fluid.Machines.PrescribedPump"]
Out[1]:=

Information

This information is part of the Modelica Standard Library maintained by the Modelica Association.

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.

Parameters (27)

allowFlowReversal

Value: system.allowFlowReversal

Type: Boolean

Description: = true to allow flow reversal, false restricts to design direction (port_a -> port_b)

energyDynamics

Value: Types.Dynamics.SteadyState

Type: Dynamics

Description: Formulation of energy balance

massDynamics

Value: Types.Dynamics.SteadyState

Type: Dynamics

Description: Formulation of mass balance

substanceDynamics

Value: massDynamics

Type: Dynamics

Description: Formulation of substance balance

traceDynamics

Value: massDynamics

Type: Dynamics

Description: Formulation of trace substance balance

p_start

Value: p_b_start

Type: AbsolutePressure (Pa)

Description: Start value of pressure

use_T_start

Value: true

Type: Boolean

Description: = true, use T_start, otherwise h_start

T_start

Value: if use_T_start then system.T_start else Medium.temperature_phX(p_start, h_start, X_start)

Type: Temperature (K)

Description: Start value of temperature

h_start

Value: if use_T_start then Medium.specificEnthalpy_pTX(p_start, T_start, X_start) else Medium.h_default

Type: SpecificEnthalpy (J/kg)

Description: Start value of specific enthalpy

X_start

Value: Medium.X_default

Type: MassFraction[Medium.nX] (kg/kg)

Description: Start value of mass fractions m_i/m

C_start

Value: Medium.C_default

Type: ExtraProperty[Medium.nC]

Description: Start value of trace substances

p_a_start

Value: system.p_start

Type: AbsolutePressure (Pa)

Description: Guess value for inlet pressure

p_b_start

Value: p_a_start

Type: AbsolutePressure (Pa)

Description: Guess value for outlet pressure

m_flow_start

Value: system.m_flow_start

Type: MassFlowRate (kg/s)

Description: Guess value of m_flow = port_a.m_flow

V_flow_single_init

Value: m_flow_start / rho_nominal / nParallel

Type: VolumeFlowRate (m³/s)

Description: Used for simplified initialization model

delta_head_init

Value: flowCharacteristic(V_flow_single_init * 1.1) - flowCharacteristic(V_flow_single_init)

Type: Position (m)

Description: Delta head for a 10% increase of flow at the initialization point

nParallel

Value: 1

Type: Integer

Description: Number of pumps in parallel

N_nominal

Value:

Type: AngularVelocity_rpm (rev/min)

Description: Nominal rotational speed for flow characteristic

rho_nominal

Value: Medium.density_pTX(Medium.p_default, Medium.T_default, Medium.X_default)

Type: Density (kg/m³)

Description: Nominal fluid density for characteristic

use_powerCharacteristic

Value: false

Type: Boolean

Description: Use powerCharacteristic (vs. efficiencyCharacteristic)

checkValve

Value: false

Type: Boolean

Description: = true to prevent reverse flow

V

Value: 0

Type: Volume (m³)

Description: Volume inside the pump

use_HeatTransfer

Value: false

Type: Boolean

Description: = true to use a HeatTransfer model, e.g., for a housing

g

Value: system.g

Type: Acceleration (m/s²)

show_NPSHa

Value: false

Type: Boolean

Description: obsolete -- remove modifier and specify Monitoring for NPSH instead

use_N_in

Value: false

Type: Boolean

Description: Get the rotational speed from the input connector

N_const

Value: N_nominal

Type: AngularVelocity_rpm (rev/min)

Description: Constant rotational speed

Inputs (1)

fluidVolume

Default Value: V

Type: Volume (m³)

Description: Volume

Connectors (4)

port_a

Type: FluidPort_a

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

port_b

Type: FluidPort_b

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

heatPort

Type: HeatPort_a

N_in

Type: RealInput

Description: Prescribed rotational speed

Components (4)

system

Type: System

Description: System properties

medium

Type: BaseProperties

heatTransfer

Type: HeatTransfer

monitoring

Type: Monitoring

Description: Monitoring model

Used in Examples (2)

PumpingSystem

Modelica.Fluid.Examples

Model of a pumping system for drinking water

BatchPlant_StandardWater

Modelica.Fluid.Examples.AST_BatchPlant